Annual Report

FRAUNHOFER INSTITUTE FOR HIGH FREQUENCY PHYSICS AND RADAR TECHNIQUES FHR

ANNUAL REPORT 2020 1 Important milestones for the GESTRA space surveillance radar in 2020: The system's transmitter and receiver unit were transported to the final location in Koblenz in the summer. This was followed by the official inauguration and handover to the German Space Situa- tional Awareness Center in the fall.

2 ANNUAL REPORT 2020 1 2 PREFACE

Dear friends and partners of Fraunhofer FHR, three new 3D printers financed by funding from Research Fab dear readers, Microelectronics Germany (FMD). These enable us to set new standards in the field of additive manufacturing. At the start of 2020, we were looking ahead with great expectation to a packed schedule full of international trade We have presented our expertise at many international online fairs and conferences, our 10th Wachtberg Forum, and a trade fairs and conferences and exchanged ideas with the large-scale Open House. Those plans were thwarted by covid scientific community in the world's major engineering associ- and we were forced to replan. We created the conditions for ations throughout the year. The excellence of our research is home office for a majority of our staff, moved events online also confirmed by the awards we have received. This year, for and found new ways to stay in touch with customers and example, Dr. Philipp Wojaczek received the Robert T. Hill Best employees – all in record time. Dissertation Award from the IEEE Aerospace and Electronics Systems Society (AESS). His work relates to projects Passive Although individual orders have fallen away, we have man- Radar & Networked RF Sensor Technology – Key Technology aged to implement our research work and projects without for FCAS and MGCS, among others (see page 28). major cutbacks. For instance, the new GESTRA space surveillance radar was handed over to the German Space Situational We hope you find the content interesting! Awareness Center – after five years of development and with an order volume of around 42 million euros. GESTRA was transported to Koblenz in July, and the inauguration ceremony took place in October. This logistical tour de force as well as the ceremony with high-profile representatives from research, Peter Knott Dirk Heberling science, defense and politics is covered on page 8.

Our new digital formats have been successfully developed. One example is the Radar in Action online lecture series, in which our scientists give application-oriented presentations of the Institute's latest research results. The half-hour lectures with demonstration and discussion in German and English are met with great interest in industry, politics, science and society. They are attended by over 100 participants from all Executive Director over the world on a regular basis. Prof. Dr.-Ing. Peter Knott Phone +49 228 9435-227 We also managed to move into Villip 2 on schedule; despite [email protected] covid. The new building at the Villip site was completed in June and subsequently became home to our interdepartmental Director Signal Processing Think Tank. The Institute continues to grow Prof. Dr.-Ing. Dirk Heberling and the new facilities are enabling this through modern offices Phone +49 228 9435-176 and laboratories. Among other things, the large hall houses [email protected]

3 TABLE OF CONTENT

Preface 3 Table of content 4

FROM THE INSTITUTE

Highlights of the year 2020 6 GESTRA milestones 2020 8 MENELAOSNT doctoral program 12 Doctorate at Fraunhofer FHR 14

OVERVIEW

Fraunhofer FHR in profile 16 Fraunhofer FHR in numbers 18 Organisation chart 20 Board of trustees 22 Research Fab Microelectronics Germany (FMD) 24

BUSINESS UNIT DEFENSE 26

Networked HF sensor technology – key technology for FCAS and MGCS 28 German-Swiss collaboration: Miniaturized radar system with livestream from aircraft to ground 30 Keeping an eye on artificial intelligence 32 Avoid blind spots in the radar 33

BUSINESS UNIT SPACE 34

Radar networks in practice: GESTRA meets EUSST 36 Space surveillance using radar networks 37 Pioneering work in commercialization 38 Higher sensitivity with deep-frozen radar receivers 39 Future TIRA – space observation radar of the future 40

4 BUSINESS UNIT SECURITY 42

Drone in flight? 44 Coastlines: Well protected . 45

BUSINESS UNIT TRAFFIC 46

More safety on the roads 48 Accurate positioning for self-driving cars 50 Time-dynamic radar simulation of traffic scenarios in real time 52 Early detection of track bed damage using radar 52 Precise material characterization 53

BUSINESS UNIT PRODUCTION 54

Using radar to check steel sheet thickness 56

BUSINESS UNIT HUMAN & ENVIRONMENT 58

Metamaterials optimize magnetic resonance imaging 60 Covid patients´ condition always in view 62 Short-range weather radars for optimized forecasting 63

ANNEX 64

Education and training 64 Publications 68 Committee activities 70 Locations 72 Imprint 74

5 Wachtberg/Online, June 5 Villip, June 1 "Fraunhofer vs. Corona" Partic- Completed on schedule: ipation in the Fraunhofer-Ge- New building in Villip sellschaft #WeKnowHow social media campaign with the key 2020 technology of radar

Bonn, March 3-5 Applied researchBesondere for defense and 3 security in Germany Washington/Online, April Dr. Philipp Wojaczek receives the Robert T. Hill Best Dissertation Award of the IEEE Aerospace and Electronics Systems Society Ereignisse2 (AESS)

Copenhagen/Online, March 15-20 1 EuCAP – The 15th European Conference on Antennas and Propagation

JANUARY FEBRUARY MARCH APRIL MAY JUNE JULY AUGUST SEPTEMBER OCTOBER NOVEMBER DECEMBER

Wachtberg, March 16 Covid-related switch to home of- Wachtberg/Online, June 23 fice for about 70% of employees Fraunhofer FHR launches "Radar in Action" Research thrives on exchange, but this is practically impossible face-to- Wachtberg, June 1 face in covid times. This is why Fraunhofer FHR is launching the Radar Ulf Herzer becomes in Action international online lecture series, in which scientists present new Head of Admin- a wide variety of the Institute's radar applications: From contactless vital istration sign detection through space observation and autonomous driving. The half-hour presentations with demonstrations and discussions in German and English are met with great interest by customers, partners and interested parties from industry, politics, science and society. These public events are attended by over 100 participants from all over the world on a regular basis. 8

Washington/Online: April 27-May IEEE International Radar Conference

Wachtberg/Online, April 16 Online through the ball: Premiere of online visitor tours 10 6 through TIRA Wachtberg/Online, June 22-25 Munich/Online, October 26-29 ORAS final presentation Fraunhofer Solution Days A special event: The final presentation of ORAS (sensor-based monitor- The Institute presents the ing and alerting system for the detection and tracking of unmanned ATRIUM radar target simulator aerial systems) was delivered under the constraints of the coronavirus pandemic. It was attended by just a few representatives on site, including project sponsor VDI-TZ. Technical University of Applied Sciences Wildau and associated partners such as BKA (the Federal Criminal Police Office) and state police forces dialed in via live stream. The associated project partners provided further information during interviews and a Q&A session. Despite the hybrid format, the demonstration was carried 7 out with no glitches and the system in use was presented successfully. Wachtberg, September 17 Expert discussion on strategy – First event with external experts in the new Villip 2 building

5 6

Wachtberg/Koblenz, June 25-July 1 Florence/Online, September 21-25 Warsaw/Online, October 5-8 Logistical tour de force: Transporting IEEE RADAR Conference International Radar Symposium GESTRA to Koblenz (see pg. 8) Prof. Peter Knott gives keynote IRS speech

JANUARY FEBRUARY MARCH APRIL MAY JUNE JULY AUGUST SEPTEMBER OCTOBER NOVEMBER DECEMBER

Wachtberg/Online, September 5 Digital Education Fair Wachtberg, November 4-5 Koblenz, October 13 2nd Fraunhofer FHR UAS Workshop Ceremony: GESTRA inauguration High-profile speakers discuss current in Koblenz (see pg. 10) developments on Unmanned Aerial Systems (UAS) with participants from Wachtberg/Online, June 25 research, industry, authorities and Hybrid Board of Trustees associations. meeting livestreamed to all employees

14 Warsaw/Online, October 5-8 Manjunath Thindlu Rudrappa wins IRS Young Scientist Contest 11 Wachtberg/Online, November 12 Virtual strategy audit

Berlin/Online, May 13 - August 15 ILA Berlin: Prominent trade fair appearance with TIRA and GESTRA

12 7 15 8 GESTRA MILESTONES 2020

Transportation to Koblenz FHR staff and the logistics company. This required two cranes with maximum lifting capacities of 350 t and 500 t Developed by Fraunhofer FHR on behalf of the German Space respectively, whose combined forces were required to lift the Agency at DLR (German Aerospace Center), the GESTRA heavy weight of the radar systems off the ground onto two (German Experimental Space Surveillance and Tracking Radar) 13-axle trailers. The heavy load got on the road on schedule at space surveillance radar completed major steps in 2020. It is 10 p.m. on June 29, 2020. As well as many vehicles for safe- currently undergoing final integration at the new Koblenz site. guarding, the convoy was also accompanied by several police vehicles. Since the loaded containers including the trailer were 7 days, 100 tons, 200 kilometers: significantly higher than 4.50 m, some highway bridges on the A logistical tour de force A3 would have been too low and the entire journey had to be made almost exclusively on country roads. In the middle of the The morning of June 25, 2020 marked the beginning of a night, around 1:30 a.m., the convoy crossed over the Rhine via perfectly planned project on Fraunhofer FHR's Wachtberg the Bonn South Bridge. It then entered the Westerwald region. campus, the likes of which the Institute had never seen before: The second stage with a total distance of about 200 kilometers Loading the GESTRA system and transporting it to its final was completed the following night, finally leading to the des- location at Schmidtenhöhe in Koblenz. Weighing almost 100 tination. GESTRA was awaited there by representatives of the tons and measuring 4 m x 4 m x 18 m each and comprising German Space Agency at DLR, the Federal Armed Forces and the transmitting and receiving module as well as both radomes Fraunhofer FHR, as well as numerous media representatives. with a diameter of 5 m, a height of 4.50 m and a weight of The two heavy-duty cranes were ready so that both containers 600 kg each, the two containers were ready for transport. and the radomes could be assembled at the destination in After one day of pure preparation time, the containers and front of the spectators the same day. radomes were loaded onto the trailers over the next two days through perfectly coordinated teamwork by the Fraunhofer

A special kind of move: GESTRA is relocated from Wachtberg to Koblenz over 7 days and nights. Via heavy transport over a 200 km route through the Westerwald region, the two 100 t containers together with the radomes arrive at Schmidtenhöhe safe and sound.

9 Research & Science, Defense and Politics: Grand Ceremony for GESTRA Inauguration

On October 13, 2020, GESTRA was officially inaugurated and handed over to the German Space Situational Awareness Center. High-profile representatives from DLR, the Fraunhofer Society and defense and politics were in attendance. During a ceremony at Schmidtenhöhe, the speakers acknowledged the significance of GESTRA for Germany and Europe and the achievements of the project participants in the development of this cutting-edge technology. Speakers included Chairman of the German Space Agency at DLR Dr. Walther Pelzer; Aerospace Coordinator of the German Federal Government Thomas Jarzombek (MdB); Fraunhofer Executive Board Member Prof. Ralf Boris Wehrspohn; Commander of the Air Operations Command (ZentrLuftOp) GenLt Klaus Habersetzer; and Interior Minister of Rhine- land-Palatinate Roger Lewentz. "Through this project, we are setting Germany apart as a location." GESTRA project manager at DLR Dr. Thomas Eversberg praised the research and development work on the space surveillance radar: "Based on our state-of-the-art systems, we are in a position to work right at the forefront of science".

After the speakers symbolically cut a ribbon to mark the opening, the guests and numerous media representatives present were able to see GESTRA for themselves. "This radar system is a piece of technology that is unique in Europe," Prof. Dirk Heberling emphasized during the event, also highlighting the special attachment which Fraunhofer FHR staff feel towards GESTRA. "I remember when the containers were delivered, employees pulled and grabbed the cables with their own hands, and that was on the weekend. This shows their commitment and passion for this project," said Prof. Heberling.

The media response to the unveiling of Germany's first space surveillance radar was huge, with print, TV, radio and social media reporting nationwide. Even the Tagesthemen news program ran a report. An exciting short film by Fraunhofer FHR summarizes the highlights of the GESTRA inauguration. The film is available at https://youtu.be/bT-oIld89Qs.

GESTRA was ceremonially inaugurated under tight covid restrictions. Guests from research & science, defense and politics took the opportunity to listen to on-site explanations of the system and gained a deep insight into the capabilities of the space surveillance radar.

10 THREE QUESTIONS TO...

Mr. Wilden, a 34-strong team has poured over 5 years of development work into GESTRA. What was the big- gest challenge during this time in your opinion?

Coming from the experience with multifunctional small radars, we were suddenly faced with the task of compiling a wish list of innovative capabilities and performance data of a Dipl.-Ing. Helmut Wilden, space surveillance radar under the constraints of partial mo- GESTRA project manager at Fraunhofer FHR bility, flexibility of a digital radar and maximum transmission power, and to design and offer the most innovative technologies for each subsystem. A major challenge in this effort was in hiring highly specialized personnel, many of whom were brought on board through the supervision of theses with system-related topics, under time constraints. This resulted in a 34-strong team which, together with the development teams of the approx. 8 main subcontractors, designed and implemented an extremely complex, multifunctional system based on effective management. The greatest challenge was to achieve and implement all system specifications through hardware, firmware and software optimizations in such a way that all necessary system components were available on time while also ensuring that the expected service life of the system of 12 years could be achieved through robust conceptual design.

What was your personal highlight?

I experienced several personal highlights during my 6 years leading this team. On the one hand, I was very pleased with the students’ commitment and enthusiasm to produce very good thesis results on the system-related topics. Transporting the system, where the constraints could only be mastered by a very experienced transport team, was definitely another highlight. Of course, the greatest joys of this development story were the final commissioning and then gradually building up proof that the performance targets were being met.

How do you let go of a project like this?

Thanks to my hobbies in crafts and music, I can let go of this project with relative ease. However, the various alternative design concepts of the individual subsystems, including signal processing, will keep my mind occupied and motivated for the rest of my days! We achieved a good starting performance with this radar demonstrator. Nevertheless, the detection performance against small debris could still be much better under the same constraints with the use of even more innovative and challenging technologies.

CONTACT Dipl.-Ing. Helmut Wilden Phone +49 228 9435-316 [email protected]

11 AUSFROM DEM THE INSTITUT INSTITUTE

PROMOTION AM FRAUNHOFER FHR

MENELAOSNT DOCTORAL PROGRAM

The European Training Network on Multimodal Environmental and the Polytechnic University of Bucharest as part of their Exploration Systems – Novel Technologies (MENELAOSNT) three-year doctoral programs. stems from an initiative of Prof. Dr. Otmar Loffeld from the Center for Sensor Systems at the University of Siegen (ZESS). The program comprises specialized lectures and courses at Dialog with Fraunhofer FHR led to the idea of establishing a the partner universities, which take place online. In addition, collaboration between renowned European institutions in the the up-and-coming scientists are offered face-to-face work- field of Compressed Sensing. After several years of planning, shops at their institutes on topics such as scientific writing, the program was initiated on January 1, 2020. MENELAOSNT communication skills, job application strategies, networking at is funded by the European Union's Horizon 2020/Marie conferences, etc. Dr. Andreas Bathelt of HRA is the program Skłodowska-Curie Actions research and innovation program. coordinator at Fraunhofer FHR. "It is great to see the results It provides 15 international early stage researchers with the the PhD students are achieving in the program. Compared opportunity to progress to a PhD via research on various to the usual tasks of the institute, whose focus is more on algorithmic and hardware-oriented tasks. the application of methods in for example industrial projects, the Horizon 2020 MSCA grant allows our ESRs to work inde- Fraunhofer FHR is one of the collaborating partners of pendently from this focus. They work independently, unlike MENELAOSNT and is supervising two early stage researchers industrial projects, for example, where the focus is always on based in the High Frequency Radar and Applications (HRA) the application for the partners. Therefore, they can go much and Cognitive Radar (KR) departments. Sanhita Guha works at more into the details depth and design new methodologies HRA, Saravanan Nagesh at KR. Both of them will also spend themselves. MENELAOSNT envisages that the PhD students’ several months conducting research at the Weizmann Institute results will also be used further later on, definitely by the of Science near Tel Aviv, as well as at the University of Siegen Institute," says Andreas Bathelt.

12 SANHITA GUHA SARAVANAN NAGESH

"I first completed a Bachelor's degree in electronics and "After completing my Bachelor's in Electronics and instrumentation technology in Bangalore, India. Then I Communications in Bangalore, India, I worked as a went to France to the Georgia Institute of Technology research fellow at the Center for Airborne Systems, in Metz. I completed my Master's degree in Electronic in the area of airborne communication and radar and Computer Engineering there, graduating in May systems. Later, I joined Robert Bosch as a senior engineer 2020. I came across MENELAOSNT while looking for an in the area of vehicle safety systems for the Asia-Pacific interesting PhD program. I am now doing research in region. Since, I was interested in learning more on the HRA department at Fraunhofer FHR for my PhD Radars, I chose to pursue a Master's degree in electrical on "Adaptive methods of Compressed Sensing for engineering, majoring in radar signal processing at the more efficient Radar Detection and Localization". I am Technical University of Delft, in the Netherlands. The working on methods that can increase the resolution MENELAOSNT program consisted of a well-structured of narrow-band radar systems using band fusion. I am career development plan with opportunities to work very pleased to be collaborating with Dr. Andreas Bathelt in top R&D establishments, this motivated me to join as my Supervisor, with Prof. Dr. Joachim Ender and Fraunhofer FHR as an Early Stage Researcher at the KR Prof. Dr. Loffeld supervising my PhD. MENELAOSNT is a department. My PhD supervisor is Prof Dr. Joachim Ender comprehensive program, where I hope to learn a lot. I and Dr María González-Huici as the supervising advisor. like networking with different professors in Europe, the My study focuses on the design of "Coded Waveform conference opportunities, the possibility to improve my for Colocated MIMO Radar using Sparse Modeling". I soft skills and German language skills. I would also like am excited about the opportunity to work on cognitive to work in the field of Compressed Sensing after my automotive radars and look forward to learning German. PhD." I trust my work, may one day contribute to reduce road fatalities."

CONTACT CONTACT Phone +49 228 9435-0 Phone +49 228 9435-0 [email protected] [email protected]

13 FROM THE INSTITUTE

DOCTORATE AT FRAUNHOFER FHR

Fraunhofer FHR offers scientists optimal conditions for writing their dissertations at the Institute. In doing so, the Institute provides each one of the employees with support that is precisely tailored to their individual interests and routes to the PhD. Two employees who completed their doctorates in 2020 report on their experiences.

Dr. Fabio Giovanneschi began his work in the present-day Cognitive Radar (KR) department of Fraunhofer FHR in 2012. DR. FABIO GIOVANNESCHI He had previously studied telecommunications engineering at "Online Dictionary Learning for Classification of Antipersonnel the University of Pisa and then worked at an Italian company Landmines Using Ground Penetrating Radar" in the field of geophysics for two years. At Fraunhofer FHR, he was involved in anti-personnel mine classification using University of Siegen Ground Penetrating Radar (GPR). "I also became interested in the Compressive Sensing theory, which was relatively new at the time, and started to apply it to my work with GPR. I CONTACT wanted to dedicate my PhD to this exciting new area." Phone +49 228 9435-143 [email protected] Prof. Joachim Ender, who was head of the Institute at the time, was very interested in the topic, so Dr. Fabio Giovanne- schi was accepted onto the PhD program at the Center for Sensor Systems at the University of Siegen (ZESS) in 2014, with Prof. Ender as the first supervisor of the PhD thesis. In the following years, however, he initially worked intensively on other KR projects as well as for the RAWIS (Radar Warning and Information System for Applications in Disaster Management) project at the University of Siegen. "I came into contact with Prof. Yonina Eldar from Technion Israel in 2016. A fruitful collaboration started on the basis of my idea to develop novel dictionary learning technology targeting a cognitive approach to the mine classification problem with GPR. This led to the publications which form the main contribution of my PhD thesis." Since completing his PhD, Dr. Fabio Giovanneschi has continued his research in dictionary learning and applied it to various radar applications, such as marine clutter suppression and LIDAR imaging.

"The collaboration with Prof. Ender is always motivating and inspiring to me. Moreover, Dr. Stefan Brüggenwirth as department head and Dr. Maria Antonia Gonzalez-Huici as team leader have always supported the research for my doctoral thesis. The colleagues in Wachtberg were also happy to engage with me and exchange ideas throughout all those years," Dr. Fabio Giovanneschi recalls.

14 After studying electronic engineering with a focus on information and communication technology at RWTH Aachen University, Dr. Christoph Wasserzier joined Fraunhofer FHR as DR. a researcher in 2009. "At first, the doctorate was not my plan CHRISTOPH WASSERZIER in the first place. Instead, I focused on exciting tasks in the present-day Passive Radar and Anti-Jamming Techniques (PSR) "Noise Radar on Moving Platforms" department, in areas where the publication of the research results is somehow difficult." Tor Vergata University of Rome

The idea to pursue a doctorate originated from a growing CONTACT interest in the field of noise radar. "The topic has always Phone +49 228 9435-228 seemed promising to me and has reached great potential in [email protected] terms of its practical applicability enabled by recent technical developments. That was appealing to me."

Dr. Christoph Wasserzier attended the PhD program at the Tor Vergata University of Rome starting in 2016. He was supervised by Professor Gaspare Galati, who has a vast experience as a researcher in this field. He traveled to Rome particularly for block seminars, but a bulk of interaction with Professor Galati took place online. "The program's clear structure allowed me to work efficiently and to combine the doctorate and activities at the Institute smoothly. My team leader Josef Worms, Prof. Daniel O'Hagan as head of department and his predecessor Heiner Kuschel always supported my PhD. Many colleagues from PSR or the workshop helped actively, especially during field experiments."

Dr. Christoph Wasserzier developed a new, real-time capable method enabling future applications in noise radar. The demonstrator he implemented in order to experimentally prove the method was received with great interest. Subse- quent uses included a NATO measurement campaign and it will continue to be used by PSR in the future. "Fraunhofer FHR provides the best conditions for successful research, not least due to the great infrastructure and equipment of the laboratories as well as the high level of technical competence of the employees. But the close collaboration with the Federal Armed Forces is what enabled the high quality of the results in the first place," he sums up the conditions of his PhD. 15 OVERVIEW

16 FRAUNHOFER FHR IN PROFILE

Fraunhofer FHR is one of the leading and largest European research institutes in the area of high frequency and radar techniques. It develops customized electromagnetic sensor concepts, processes, and systems for its partners, from the microwave range through to the lower terahertz range.

The core topic of the research at Fraunhofer FHR consists of affordable and attractive option for an increasing number of sensors for high-precision distance and position determination application areas. as well as imaging systems with a resolution of up to 3.75 mm. The applications range from systems for reconnaissance, Staff and budget development surveillance, and protection to real-time capable sensors for traffic and navigation as well as quality assurance and non-de- The Institute's budget comes from several sources of financ- structive testing. Fraunhofer FHR's systems are characterized ing: The basic financing from BMVg, the project financing by reliability and robustness: Radar and millimeter wave through funds from the defense budget and the income from sensors are suitable for demanding tasks, even under rough the contract research area (Vfa), which in turn can be subdivid- environmental conditions. They work at high temperatures, ed into economic revenues, public revenues, EU revenues and with vibrations, or under zero visibility conditions caused the basic financing by the federal government and the federal by smoke, vapor or fog. Thus, radar and the related high states. In 2020, in its defense and civil segments, Fraunhofer frequency systems, are also key technologies for defense and FHR generated total income of €38.0 million. security. In this area, the Institute has been supporting BMVg (the German Federal Ministry of Defense) since the Institute Fraunhofer FHR had a total headcount of 390 at the end of was founded in 1957. 2020. Of these, 207 are permanent employees and 129 are temporary. The 54 remaining employees are students and On one hand, the processes and systems developed at apprentices. Fraunhofer FHR are used for research of new technology and design. On the other hand, together with companies, authorities, and other public entities, the Institute develops prototypes to unsolved challenges. The special focus here is on the maturity of the systems and their suitability for serial production to ensure a quick transformation into a finished product in cooperation with a partner. Thanks to its inter- disciplinary positioning, the Institute possesses the technical know-how to cover the entire value creation chain, from consulting and studies up to the development and production of pilot series. The used technology ranges from the traditional waveguide base to highly integrated silicon-germanium chips with a frequency of up to 300 GHz.

The ability to carry out non-contact measurements and the penetration of materials open up a range of possibilities for CONTACT the localization of objects and people. Thanks to the advances Dipl.-Volksw. Jens Fiege in miniaturization and digitalization, the high frequency Phone +49 151 613 653 67 sensors of Fraunhofer FHR with their special capacities are an [email protected]

17 OVERVIEW

FRAUNHOFER FHR IN NUMBERS

18 19 OVERVIEW

ORGANISATION CHART

20 21 OVERVIEW

22 DASTHE BOARDKURATORIUM OF TRUSTEES

DasThe BoardKuratorium of Trustees begleitet supports unsere our Forschungsarbeit research work andund advisesberät den the InstitutsleiterInstitute Director und andden theVorstand Executive der FraunBoardhofer-Gesellschaft. of the Fraunhofer-Gesellschaft. Die Mitglieder The unseres members Kuratoriums of our Board aus Industrie, of Trustees Wissenschaft from industry, und scienceMinisterien and sind:ministries are:

Chairman Dipl.-Ing. Gunnar W. R. Pappert DIEHL DEFENCE GmbH & Co. KG Röthenbach a. d. Pegnitz

Dr. Gerhard Elsbacher Prof. Dr.-Ing. Martin Vossiek MBDA Deutschland GmbH University of Erlangen-Nuremberg Schrobenhausen Erlangen

Hans Hommel Prof. Dr.-Ing. Christian Waldschmidt Hensoldt Ulm University Ulm Ulm

Dr. Holger Krag MinRat Norbert Michael Weber ESA / ESOC Federal Ministry of Defence (BMVg) Darmstadt Bonn

Prof. Dr.-Ing. habil. Otmar Loffeld Winfried Wetjen University of Siegen OHB-System AG Siegen Bremen

Prof. Dr.-Ing. Ilona Rolfes Ruhr-University Bochum Bochum

Due to the covid restrictions, the meeting of the Board of Trustees on June 26, 2020 was different than usual: Only a few participants attended in person, most of them were connected virtually – a first in the history of the Institute. This time, the report of the Executive Board was given by Dr. Markus Zirkel, Head of the Fraunhofer Society’s Legal Department.

23 OVERVIEW

1 The HAGE3D allows printing with both filament and granules. The maximum print area is 1200 mm x 1200 mm x 1000 mm in 3-axis mode, while 5-axis mode allows complex components to be printed without support material, saving time and material. 2 As part of FMD, investment was made in a millimeter-wave measurement laboratory. The interior view of the anechoic chamber shows a measurement device for antenna characterization, but subsystems and complete prototypes can also be assessed.

RESEARCH FAB MICROELECTRONICS GERMANY (FMD)

Companies need perseverance for developments in the semiconductor segment: Numerous individual institutes have to be contracted. For this reason, the Research Fab Microelectronics Germany has now combined the expertise of different research institutes, including Fraunhofer FHR. Thanks to a number of new acquisitions, technologies can now be used that were not available before in Germany.

When medium-sized businesses or start-ups need develop- For instance, the circuit design would be done by FHR, the ments in the semiconductor segment, they are often faced production at IHP in Frankfurt/Oder or at Fraunhofer IAF in with difficulties. After all, it is rare for a single research Freiburg, the packaging would be done at Fraunhofer IZM in institute to cover all required competencies. For companies, Berlin, and finally, Fraunhofer FHR would have to get involved this means the following: They have to contact multiple again for the radar and antenna inspection. The company institutes and conclude many individual contracts – a tremen- would only negotiate with FMD for this entire chain. dous effort. This is where the Research Fab Microelectronics Germany, FMD in short, comes in: Following the example Antenna anechoic chamber for complex radar systems of large microelectronics institutes abroad, it combines the German competencies, establishing a joint virtual structure. One of the key competencies Fraunhofer FHR contributes The cooperation is made up of eleven Fraunhofer Institutes to FMD is antenna measurement technology. What are the of the Fraunhofer Group for Microelectronics and the two properties of antennas for radar systems – for example, what Leibniz Institutes FBH and IHP. BMBF (the Federal Ministry of are their directional characteristics? In the future, an antenna Education and Research) provided a total 350 million euros in anechoic chamber acquired within the scope of the FMD funding for the creation of the FMD – in particular to close the will allow for accurate examinations of individual and array technological gaps between the institutes and to introduce antennas in the frequency range from 300 MHz to 50 GHz. technologies which had not been available yet in Germany. The chamber itself has been completed. The range assessment Fraunhofer FHR primarily contributes its expertise in the areas is currently still in progress – that is the verification of the test of high frequency techniques, antenna measurement technol- area. This involves the anechoic chamber being characterized ogy, and the production of circuit boards, radar modules, and according to specified criteria in order to be able to prove the high frequency structures. quality of the measurements. As of late, even the smallest of antennas can be analyzed at Fraunhofer FHR using FMD Customers get to enjoy the direct benefits of this cooperation. infrastructure: For instance on-chip antennas, i.e. antennas They only have to contact one contact person, they receive a with a size of one to two millimeters integrated into a chip. single contract, and they obtain the entire development chain from a single source. Let us take a radar chip as an example:

24 1 2

Additive manufacturing of high frequency circuit boards range up to 500 GHz using an on-wafer probe station . The FMD equipment at Fraunhofer FHR allows these subsystems to Another new acquisition addresses the additive manufacturing be measured up to one terahertz for their intended use. The of high frequency structures: Industrial-scale metal and plastic equipment used for this purpose includes an anechoic anecho- printers. Whereas the 3D printers we are familiar with from at ic chamber, which allows the characterization of subsystems, home are only capable of producing small structures and low objects and materials of eight gigahertz and upwards. For quantities, these printers make it possible to produce volumes example, the expected radiation power of built-up radar front of up to one cubic meter. Another special feature: The metal ends can be checked as a function of frequency. A climatic printer is also capable of printing waveguide structures. The test chamber rounds off the measurement possibilities. This al- plastic printer opens numerous new possibilities as well, for lows the systems to be examined under different temperatures example printing antenna structures, lenses, and housings. and humidities. With the help of various types of software, the measuring devices can be specifically controlled using certain Producing printed circuit board prototypes at short parameters such as wave form and noise and evaluated on the notice receiving side. This allows Fraunhofer FHR to simulate various application scenarios for the subsystems and test them directly Thanks to the FMD's investment resources, FHR was able to for specific properties such as signal linearity. acquire a variety of devices, including a laser milling machine, placers and bonders, to produce printed circuit boards – quickly and on short notice. This enables Fraunhofer FHR to create CONTACT subsystems, e. g. for signal generation, as well as entire radar Daniel Behrendt systems. To test the subsystems, the printed circuit boards Phone +49 151 120 101 64 are measured right inside the circuits in the high-frequency [email protected]

25 BUSINESS UNIT DEFENSE

Radar is a key technology in defense issues – traditional applications include airspace surveillance and remote imaging reconnaissance. The Business Unit Defense supports the Federal Armed Forces, among others, with its expertise in this area.

Radar technologies can also be useful at close range, for example for the active protection of military vehicles.

If covert reconnaissance is required, passive radar can be used to detect existing radio waves. The first passive system for air surveillance was developed and commercialized in Germany in the Business Unit Defense.

Initial results have also been achieved in the field of cognitive radar, which performs its own parameterization.

26 RADAR IN THE SERVICE OF DEFENSE

Reconnaissance in crisis areas, surveillance of the airspace, The Business Unit Defense implements the radar detection of protection of military vehicles: When it comes to defense, ra- projectiles required for active protection. dar is a key technology – after all, it allows for the radio-based detection and measurement of objects. Fraunhofer FHR's Any attempts undertaken by other countries to explore the Business Unit Defense offers a high degree of expertise in circumstances in Germany are in no way appreciated. For this radar technologies that are frequently used by the Federal reason, the Business Unit Defense also works on deceiving or Armed Forces and the military industry. jamming radar systems with the corresponding transmitters – to impede or prevent any exploration by this means. Passive Air space surveillance and radar imaging for remote radar is an ideal solution to conceal one's own observations reconnaissance and to thus protect them against these types of jamming attempts. In doing so, you do not emit the signals yourself but An important task of the Federal Armed Forces consists in instead use the radio waves of others to monitor the airspace – detecting objects in airspace and low Earth orbit, whether without making yourself noticeable. The Business Unit Defense these are aircraft, rockets, or even satellites. Therefore, the was also productive in applying its expertise in this area of radar systems developed in the Business Unit Defense on the concealed reconnaissance: It developed the passive system for one hand, monitor the airspace from Earth – with the radar air surveillance. systems looking up into the air from the ground. On the other hand, radar systems mounted on aircraft or satellites monitor Cognitive radar is still a rather new field of research for the Earth from above. Such an image-based distant reconnaissance Business Unit Defense. Achieving the optimum setting of allows for the measurement of both buildings and other static a radar system for its use is usually a complex challenge. objects as well as moving objects such as cars and trucks. The aim for the future is for radar to be able to carry out its Another task of radar systems consists in determining target parameterization itself and adapt it to the task based on its classes: For example, helicopters, rockets, or similar objects are own intelligence since it makes a big difference if images of distinguished in the air, while individual buildings and even the areas with high mountains or over the ocean with powerful types of agricultural areas can be recognized on the ground. waves have to be obtained. Excellent results have already been achieved in this area of cognitive radar. Other, still relatively A general trend that is starting to emerge in the radar field: new, research fields are the design of metamaterials – i.e. The use of higher frequencies is increasing. On one hand, materials with properties that do not exist as such in nature – this makes it possible to implement smaller and lighter radar allowing for special features in antenna design – and coherent systems and on the other hand, the usual frequency range is radar networks in which multiple transmitters and receivers getting crowded due to increasing mobile communications work together to emit their signals so that they are finely and wireless networks. With its 300-gigahertz radar, the attuned to each other. Business Unit Defense is in the big leagues on an international level.

Further radar developments for defense

Radar is also a practical solution for some close range issues as well as it is capable of imaging the surroundings even in dark- Contact: ness or foggy conditions. This can be important on drones or Spokesman Business Unit Defense other unmanned flying objects, on robots, or on vehicles, for instance. On military vehicles, it is possible to recognize when Dr.-Ing. the vehicle is being fired on: For example, when a grenade UDO USCHKERAT is approaching, the tenths or even hundredths of a second Phone +49 151 721 243 27 are crucial to be able to initiate active protection measures. [email protected]

27 BUSINESS UNIT DEFENSE

1 Bistatic SAR image of an airfield and a village, captured by the TerraSAR-X Earth observation satellite as transmitter and the PAMIR flying radar system as receiver. 2 HF module for synchronization of radar transmitter and remote receivers. 3 Deep-learning approach to the classification of airborne targets using radar.

NETWORKED HF SENSOR TECHNOLOGY – KEY TECHNOLOGY FOR FCAS AND MGCS

Two major projects are on the agenda at the Federal Armed Forces: Future Combat Air System (FCAS), in which a new combat aircraft including unmanned escort airplanes is to be developed, and Main Ground Combat System (MGCS), in which the development of a new tank is making strides. NATO is working on the AFSC major project. All three major projects represent complex system-of-systems requiring networked HF sensor technology – a core competence of Fraunhofer FHR.

Pilots in combat aircraft have to accomplish a lot: They have to – otherwise the quality of the images would be compromised. keep the aircraft airborne and navigate while also operating Using the new synchronization module (Fig. 2), this can be and evaluating the radar more or less on the side. The carried out via the normal radar antenna. It has also been Franco-German-Spanish FCAS major project therefore aims demonstrated at Fraunhofer FHR already: A bistatic SAR image to significantly increase the level of automation in order to can be generated using a satellite illuminator as transmitter reduce the pilots' workload. Apart from that, it is planned that and the PAMIR airborne radar system as receiver (Fig. 1). manned combat aircraft will in the future be accompanied Another part of the development tasks lies in intelligent signal by drones with integrated HF sensor technology, allowing processing and software development. This also falls under the significantly more situational information to be generated. umbrella of "cognitive radar" – after all, artificial intelligence The drones are equipped with radar or HF receiver systems and machine learning methods are used here (Fig. 3). And, of for this purpose; combined with the aircraft, they can form a course, hardware is also involved, such as compact broadband multistatic radar. and energy-efficient radar systems. Novel manufacturing processes and materials are also used for this purpose. All This can only be achieved using networked HF sensor tech- competencies that are necessary for the development of nology. Such a system is being developed at Fraunhofer FHR. networked sensor technology are available at Fraunhofer Networked sensors can be used to protect human lives, since FHR – the researchers work together across departments. the manned platform does not have to move into engagement The basic technologies required for FCAS have already been range, while it also improves all-round visibility and optimizes developed. Plus, unique in Germany: Fraunhofer FHR even reconnaissance. A multi-platform system also achieves better has initial experimental prototypes of the multistatic radar classification of the target, so it is much easier to determine already. This was used to verify the theoretical results at the from the images what kind of object is at hand. Mönchsheide airfield during a measurement campaign. While two radar sensors were operated on the ground, one receiver Synchronization between transmitters and receivers is elemen- was located on FHR's own ultralight aircraft Delphin. Another tary for networked sensor technology: The systems must be aircraft circled over Mönchsheide as a "target object". fully in sync, accurate down to fractions of the wavelength

28 1

2 3

Networked HF sensor technology on the ground AFSC: A NATO major project

Networked HF sensors are playing an increasingly important Networked sensor technology is also important in the AFSC role not only in the air, but also on the ground. For instance, (Alliance Future Surveillance and Control) major project. AFSC tanks have to withstand ever-increasing combat strength, is a successor program to AWACS – this involves ground which is why their armor is getting thicker all the time. How- stations as well as manned and unmanned flying platforms ever, this makes them heavier and heavier, so crossing bridges and satellite stations. Here, too, radar systems, especially can quickly become difficult, and transporting them by air and synchronization, are an important basis. A basis for which ship edges towards the realm of the impossible. This is why Fraunhofer FHR is developing the necessary technologies. the Federal Armed Forces is combining several small vehicles: Operating together, they should have the same combat power as a large tank, but be better protected by sensor technology. As part of the Main Ground Combat System (MGCS) project, Germany and France are developing a new battle tank envis- aged in the long term as being supported by self-driving escort vehicles. However, in areas without infrastructure, communication between the vehicles poses challenges. Fraunhofer FHR is CONTACT developing a solution: Using sensor technology as a means of Dr.-Ing. Stefan Brüggenwirth communication at the same time. Phone +49 228 9435-173 [email protected] In other current research, Fraunhofer FHR is working on improving the resolution of radar images. This can be done, for Prof. Dr. Daniel O`Hagan example, by having the radar systems of two vehicles look at Phone +49 228 9435-389 the same point – this would significantly improve the detection [email protected] capability at greater distances as well as the resolution. The resolution could also be improved immensely using a bistatic Dr. rer. nat. Stephan Stanko radar and stealth effects could even be evaded. Fraunhofer Phone +49 228 9435-704 FHR has a great deal of expertise in this area also. [email protected]

29 BUSINESS UNIT DEFENSE

1 Polarimetric SAR image (red: co-polar, green: cross-polar) of Mönchsheide airfield. 2 Four-channel MIRANDA35 radar system in wingpod of Delphin ultralight aircraft showing the four receiving antennas and the transmitting antenna of the radar front end. 3 Ground control station with telemetry antenna in a field south of Bad Breisig during the 2020 measurement campaign.

GERMAN-SWISS COLLABORATION: MINIATURIZED RADAR SYSTEM WITH LIVESTREAM FROM AIRCRAFT TO GROUND

Imaging techniques such as radar are extremely important for the Federal Armed Forces; airborne sensors in particular provide a great deal of information. A radar system which Fraunhofer FHR developed in a German-Swiss collaboration and is continuously optimizing can detect moving targets as well as differences in altitude. The captured data was sent directly to FHR's own ground control station during a test flight.

A picture is worth a thousand words? This saying does indeed plane. If they encounter edges, corners and similar man-made carry some truth. The Federal Armed Forces appreciates im- objects, their polarization direction can rotate. Valuable aging techniques too – especially the good overview from the conclusions can, in turn, be drawn from this rotation. air. Has anything in the surrounding area changed since the last overflight? Is there anything moving on the ground, for Test flights with ultralight aircraft example a tank? In a German-Swiss collaboration, Fraunhofer FHR, the University of Zurich and Armasuisse are working to The German-Swiss collaboration has already existed for over answer such questions as accurately as possible via radar. Their ten years: Fraunhofer FHR develops the hardware (MIRAN- high-resolution, four-channel SAR (Synthetic Aperture Radar) DA35 radar system) and organizes the test flights, while the allows changes to be detected, moving objects identified and University of Zürich handles the evaluation. The developments even differences in altitude determined. are financed by Armasuisse. The newly implemented techniques have to pass a practical test once a year: Do they The system's four receiving antennas are laid out in a cross deliver the desired results? The system has now been scaled shape – data is recorded on all four channels at the same down so that it can be carried by Fraunhofer FHR's Delphin time. This allows "along track" information to be obtained, ultralight aircraft: To do this, all components of the radar for example to detect moving targets on the ground, while at system had to be accommodated in a small wingpod under the same time recording the "cross track" data, from which the right wing. Staying within the Delphin's load capacity was differences in altitude, for example, can be detected using in- a major challenge. terferometry. In addition to the radar data, the system records optical camera images, which are also sent to the ground The test flights with the ultralight aircraft, starting from and facilitate the interpretation of the radar images. One of Mönchsheide airfield and flying over Koblenz, the Rhine Valley the four receiver channels is also designed for polarimetric and the surrounding area, took place from September 21 to operation: The emitted radar waves are linearly polarized in a 24, 2020. In order to detect moving targets, the Delphin also

30 1

2 3

flew over the Rhine ferry in Königswinter several times. A GPS In a further development, Fraunhofer FHR is now working on transmitter on the ferry provided control values. The results are enabling measurement at high altitudes with full bandwidth impressive: All components are fully functional and deliver the (high range resolution). The background: The radar system desired high-resolution SAR images. illuminates the ground at a certain angle. If the aircraft climbs a little, the illuminated area expands and the amount of data Special features: Online SAR and dedicated ground increases. In the future, the system will be able to deliver station high-resolution images even at higher altitudes with the aid of an expansion board. The data is processed on board the Delphin in real time and sent to the ground station as image files. This is because the raw data would be far too large to be send to the ground during the flight. Such online SAR offers a considerable advantage: Operators on the ground receive the images during the overflight and can, for example, immediately signal to the pilot to fly back over an interesting spot. Another special feature: Fraunhofer FHR operates its own ground control station and is thus completely self-sufficient. From there, the radar can be controlled, the flight track managed and monitored, and data within a radius of 40 to 50 kilometers from the aircraft received. Since the station is installed in a van, it is mobile. CONTACT Dr. rer. nat. Michael Caris Phone +49 228 9435-353 [email protected]

31 BUSINESS UNIT DEFENSE (a) Input (b) Heatmap (c) Overlay

Imaging of a tank: radar data (a), heat map (b), and the comparison of the evaluated imaging locations (c).

KEEPING AN EYE ON ARTIFICIAL INTELLIGENCE

Automatic and smart data analysis is needed in many areas. This is usually achieved using artificial intelligence, which in turn is often based on neural networks. However, what exactly these neural networks do in their decision-making processes is mostly unknown. Fraunhofer FHR is now investigating the processes that were previously still in the dark.

Artificial intelligence and neural networks are hot topics that The analysis was carried out using both feature maps and run through numerous areas – from mobility and production heat maps. The algorithms they use are known, but they have processes through defense. After all, the data volumes not yet been applied to the analysis of radar data. Visualizing collected are becoming increasingly large, so the support feature maps at each individual layer helps to understand needed for their evaluation is growing steadily. Although the what the neural network learns in order to make a specific neural networks generally deliver good results, usually it is not decision or prediction. The focus here is on features such as known how they arrive at these results. The neural networks edges or the length of the target. However, in deep neural are similar to a black box. Sometimes they rely on unimportant networks, this type of analysis quickly becomes confusing. This information when performing an image classification task. For reason is that the deeper the network gets, the more complex example, in one project described in the scientific literature the feature map becomes. Therefore, all important features which involved the classification of ships in optical images, the that the neural networks "look at" were combined in a heat neural networks analyzed the water instead of the ships! map in a second analysis. The results validate Fraunhofer FHR's neural networks: As desired, they analyze the targets, not the Do neural networks do what they are supposed to do? Are background. their results therefore reliable? Researchers at Fraunhofer FHR are investigating these questions under the heading of Ex- plainable AI. The work is based on public radar data obtained during two overflights over a field. Ten targets were placed on the field beforehand – tanks, trucks, armored vehicles and a bulldozer. The radar data generated during the first overflight was used as training data. The test data was collected during the second overflight as the targets remained untouched and only the observation angle was modified. It would thus be CONTACT entirely possible for the neural networks to classify the radar M. Sc. Simon Wagner images by background, such as a tree standing next to the Phone +49 228 9435-365 tank. [email protected]

32 BÖKLER

Received signal in the frequency range with (green) and without (red) RPC.

AVOID BLIND SPOTS IN THE RADAR

Whether in communications or in radar, transmission and receiving operation cannot be performed simultaneously. The reason for that is the strong transmission signal would drive the sensitive receiving ampli- fiers into satiation. Fraunhofer FHR is developing technologies that allow simultaneous transmission and receiving operation. Thus blind areas can be avoided using radars and for the communication sector the throughput can be doubled.

Constriction can sometimes be detrimental. For example, in receiving branch so that the crosstalk signal is canceled – this radar or communications systems with their powerful trans- is also referred to as Reflected Power Cancellation (RPC). Thus, mission units and sensitive receiver stages. Only one antenna is signals of any waveform can be sufficiently suppressed. A used in these cases for reasons of cost and space. Performing digital approach takes care of the finishing touches: It prepares a simultaneous transmit and receive at the same time is out the cancellation signal so that this can take place over a of the question. The reason is that when the transmitting very wide bandwidth. A prototype has already been created stage wants to radiate its powerful signal to the world, part and initial measurements are currently underway and shows of this power is coupled to the receiving branch. This quickly remarkable results. saturates the sensitive receivers – in the worst case, damaging it. Until now, the solution has been to operate the transmitter The advantage of this technology is that blind spots in the and receiver alternately. In communication systems, different radar can be avoided. As far as communication is concerned, frequencies for the transmit and receiving branches and very the data rate can potentially be doubled – assuming simulta- steep-edged filters in the front end also provide a remedy. neous transmission and receiving. Radar and communication However, this is not possible with radar. The alternating can even be linked and their simultaneous operation enabled. operation thus results in a dead zone – an area in front of After all, both require the same front end. the radar where it cannot detect any targets. This is because signals reflected from nearby objects reach the receiver while the transmitter is still transmitting and the receiver is switched off. Operators of such systems therefore want to be able to transmit and receive simultaneously.

Simultaneous operation of radar and communication

In the STAR project, Fraunhofer FHR is working to realize such CONTACT simultaneous use; which is enabled by a multi-stage process. Dr.-Ing. Matthias Weiß In the first stage, the instantaneous transmission signal is Phone +49 228 9435-267 modified accordingly in a parallel branch and coupled into the [email protected]

33 BUSINESS UNIT SPACE

The density of satellites and space debris in the low-Earth orbit is increasing rapidly. This involves increasing hazards.

Fraunhofer FHR's Business Unit Space’s TIRA and GESTRA radar systems can be used to monitor, observe and identify objects in low- Earth space. The two systems complement each other in an optimal way.

The GESTRA radar system, which is being developed for DLR Space Management, can acquire the orbital data of numerous objects very quickly and across a large section of space at the same time.

If an object is to be detected more accurately, the TIRA radar system is a good choice: It is already in use and can detect and image objects precisely. 34 SPACE: PRECISE DETECTION OF THE POSITION OF OBJECTS

Freeways and highways in metropolitan areas are not the only enables statements to be made about the satellite itself. If places where traffic density is high. Low-earth space is also a satellite is not working, for example, TIRA can be used to very busy and sometimes crowded: It is littered with active clarify whether this may be due to the solar panel not being satellites as well as space debris, and their density is increasing deployed correctly. The ability to image space objects in high rapidly. Similar to road traffic, this involves increasing dangers. definition using TIRA is unique in Europe, which is why the After all, if collisions occur, satellites can be destroyed, affect- system has already supported numerous missions. ing infrastructure that is vital to society (e.g. satellites used for navigation or communications). It is therefore essential to To date, the Business Unit Space has been focusing on the detect, monitor and track space objects: By keeping an eye on aforementioned space situational awareness of space objects. the objects circling around at all times, in the event of immi- Other areas of activity are to be added in the future. Firstly, nent danger, countermeasures, such as evasive maneuvers by there are plans to supplement Earth-based SSA sensors with satellites, can be initiated in good time. Therefore, Space Situ- space-based radar. In this case, the radar system that observes ational Awareness (SSA) is one research topic that is becoming the space objects is no longer located on Earth, rather on a increasingly important in both the European and international satellite in orbit. Secondly, the portfolio is to be expanded with context. This area of research is also gaining in significance the inclusion of other research topics. Examples include active from a military viewpoint: Suspicious maneuvers in which antenna technologies for communications satellites, SAR spy satellites approach or even dock on other satellites are (Synthetic Aperture Radar) technology for Earth observation on the rise. New space powers such as India and China have satellites and satellite-based microwave radiometers for tested anti-satellite missiles to showcase their capabilities. The climate and environmental research. The Business Unit Space U.S. recently established a space army due to the increasing will therefore be even more broadly positioned in the future threat in and from space. France has also announced a plan to than it has been to date, allowing other space research fields develop laser weapons for defense reasons. to benefit from its major competencies also.

GESTRA and TIRA: Hand in hand

The radar systems researched and developed by Fraunhofer FHR's Business Unit Space are ideally suited to monitoring, observing and identifying objects in low-Earth space. In this context, the TIRA and GESTRA radar systems complement each other in an optimal way. The GESTRA radar system, which is being developed on behalf of DLR German Space Agency, allows continuous monitoring in wide-range space. It can be used to determine the orbital data of many objects simultaneously. Moreover, it has the capability to determine the altitude of the objects as well as their inclination – the degree between the Earth's equator and their orbit. Another special feature: GESTRA combines phased array antennas, mechanical mobility of the radar units in three axes, and mobility of the Contact: entire system. GESTRA can thus be deployed at any location, Spokesman Business Unit Space enabling a network of radar systems for space surveillance. M. Sc. If, on the other hand, a specific satellite or other space object YOUNGKYU KIM needs to be detected with more precision, the TIRA system Phone +49 160 2633 836 already in use is the system of choice. It allows satellites to be [email protected] detected and imaged much more precisely – and additionally

35 BUSINESS UNIT SPACE

Diagram of radar network for space surveillance consisting of GESTRA EUSST receiver (foreground) and GESTRA system (background).

RADAR NETWORKS IN PRACTICE: GESTRA MEETS EUSST

Networks consisting of several radar units are far superior to individual radar systems. This has already been shown in a study by Fraunhofer FHR and will now be demonstrated in practice by the GESTRA EUSST project. To this end, the GESTRA space observation radar is to be coupled with a newly developed receiver called EUSST. In the future, the two systems will be spatially separated but networked to provide more precise information.

Communication, navigation, weather forecasting, television – system called EUSST. The second part comprises implementing all of these rely on satellites. If one of them fails, this can have the "operating system" that allows GESTRA and EUSST unforeseen consequences. But such a failure is by no means to work together. Finally, by combining both systems, a improbable: After all, pieces of scrap of all kinds are buzzing functional radar sensor with significantly improved resolution around in the low-Earth orbit. If they hit a satellite, the satellite as well as more precise situation and orbit estimation should may be destroyed by the force of the impact. Satellite opera- be produced at the end of the project. The design of EUSST tors therefore have a great interest in detecting scrap particles is similar to that of GESTRA, but with the addition of various in orbit and determining their trajectories – and triggering components which are necessary for networked operation. the satellite to execute an evasive maneuver in the event of Also, unlike GESTRA, EUSST is intended to be a pure receiver imminent danger. This can be done by the GESTRA radar with no transmitting unit. GESTRA is also being optimized for system, which Fraunhofer FHR has been building since 2014 collaboration: In particular, the software and algorithms need and is currently completing. GESTRA reliably detects larger to be adapted for networked operation. Another development pieces of scrap. However, the system’s current resolution has aspect is that the time synchronization of both radar systems its limits. Therefore, even during its construction period, the is required to be highly stable. This is achieved using long-term consideration was: How can GESTRA’s resolution be improved stable atomic clocks. so that smaller "projectiles" can also be reliably detected? As a study by Fraunhofer FHR showed (see article on page 37), the answer lies in radar networks.

Practical test for radar networks

The GESTRA EUSST project, which started at the beginning of CONTACT 2021, now presents the practical test: How can radar systems Dipl.-Ing. Markus Gilles be interconnected in real life? The project was commissioned Phone +49 228 9435-523 by DLR. The first part of the project involves building the radar [email protected]

36 Comparison of detections and resulting scatter of estimated object position after one circuit of the orbit. Left: Single station consisting of transmitter (Tx) and receiver (Rx). Right: Multistatic network consisting of three stations (Tx and Rx).

SPACE SURVEILLANCE USING RADAR NETWORKS

We are stronger when we join forces – this is true not only for humans, but for radar systems as well. A study by Fraunhofer FHR in collaboration with Fraunhofer FKIE shows that if radars are interconnected to form networks, this increases the monitoring range, allows more precise positioning and increases the probability of detection, as the signal-to-noise ratio and thus the sensitivity can be optimized.

Is there an imminent danger of space debris colliding with a satel- adding up the signals from the individual radars in the network, lite? Fraunhofer FHR develops and operates various radar systems such that the noise components partially cancel out each other, that monitor space and answer such questions. The amount of allowing for an optimization in the signal-to-noise ratio and thus space debris is rapidly increasing and even a single screw can an increased sensitivity. disable a satellite. This raises the question how space monitoring using radars can be further improved. Radar networks present Although the extent to which the performance of space one promising possibility. While radar units are located close to surveillance can be increased is dependent on the objects being each other in local networks, in medium-extent networks they are observed as well as the network geometry and processing, the located several hundred kilometers apart. general rule is: The more radars, the better the performance. In case of three interconnected receivers – and the ideal case of Radar networks offer numerous advantages coherent processing – the detection performance improves by up to a factor of three, with four receivers respectively by up to a In collaboration with Fraunhofer FKIE, Fraunhofer FHR investigated factor of four, and so on. Fraunhofer FHR, in collaboration with the advantages offered by radar networks. The investigation Fraunhofer FKIE, is to continue its investigations in a three-year was carried out on behalf of DLR as part of a three-year research follow-up project with DLR starting in January 2021. Among other project funded by the German Federal Ministry for Economic things, the focus here will be on resource management, i.e. the Affairs and Energy. The results: If the radar systems are looking question how radar networks can be operated as efficiently as in different directions, the monitoring area can be significantly possible. increased. In contrast, if they are looking at the same object, its position can be determined much more precisely, since each of the receivers is looking at the object from a different angle. More- over, the target velocity vector can be determined by measuring at a single point in time, whereas a single radar can only achieve CONTACT this by means of observations at different times. In addition, the Rudolf Hoffmann probability of detection can be increased using radar networks Phone +49 228 60882-2242 compared to the individual radar systems. This is achieved by [email protected]

37 BUSINESS UNIT SPACE

GESTRA shipping container at the final location in Koblenz.

PIONEERING WORK IN COMMERCIALIZATION

Be it the Federal Armed Forces, or telecommunications companies: Satellite operators want to protect their satellites from colliding with space debris. The GESTRA phased array radar, developed by Fraunhofer FHR, can do this. The Institute is currently working to commercialize GESTRA with an industrial partner. There is great interest both nationally and internationally.

What is buzzing around in the low-Earth orbit (LEO), and series production requires a long-term collaboration with one where? This question is not only interesting in itself, but also or more industrial partners. Partnering with one or several entirely relevant to our everyday lives. After all, the LEO is the German industrial enterprises would be ideal, as GESTRA is orbiting location of the satellites that supply us with informa- considered a safety-relevant key technology. tion – be it for navigation systems or critical infrastructures such as communications, the stock exchange and others. Fraunhofer FHR strives for a close collaboration with the A lot of space debris, which poses an increasing threat to partner – after all, the transfer of know-how has to be the satellites, is also floating around up there. Monitoring ensured. It will also accompany the development-related steps the low-Earth orbit and knowing what moving objects it as a consultant and provider of know-how: The steps towards contains requires a phased array radar with elevated beam the finished product are to be taken side by side. As simple agility. Working on behalf of the German Federal Ministry as this may initially sound, the commercialization of such a of Economics, Fraunhofer FHR has developed one of these complex system at this scale has never occurred before at the as an experimental system. The GESTRA semi-mobile space Fraunhofer Society. As a result, there is no blueprint for the surveillance radar was handed over to DLR and the German processes it requires. To a certain extent, pioneering work Space Situational Awareness Center in September 2020. needs to be done here to pave the way for other large-scale projects as well. This will benefit not only research and indus- Breaking new ground: Side by side with industry try partners, but also end customers, who will thus be able to access new technological developments at an earlier stage. Fraunhofer FHR is now working on bringing the system into commercial use. Potential end customers, such as the Federal Armed Forces, are showing great interest in Germany's first space surveillance radar – not just nationally, but worldwide. The challenge: At present, the sensor is still at a stage where CONTACT it cannot as yet be commercialized directly. Transforming Dipl.-Ing. (FH), BW Markus Postma this experimental system into a marketable product ready for Phone +49 228 9435-79043 [email protected]

38 Scalable cryogenic 7-element receiver array in preparation for high frequency measurements.

HIGHER SENSITIVITY WITH DEEP-FROZEN RADAR RECEIVERS

If the smallest satellites in orbit are to be monitored or if radar is to be used to look as far as possible into space, the radar systems must have a good level of sensitivity. But weak signals are quickly masked by the inherent noise of the receivers. Cryogenic technology can help: If the receivers are cooled to four degrees Kelvin, sensitivity can be expected to double. Such a cryo-receiver is currently being developed at Fraun- hofer FHR.

Thousands of cube sats are already buzzing around in third challenge lies in the vacuum container itself: Not only low-Earth orbit – small satellites, sometimes no bigger than does it have to withstand the pressure difference between an orange. And the number is constantly increasing. To be the atmosphere and the vacuum, but it must also provide able to see them with radar equipment or to look into more thermal insulation and be permeable to certain high-frequency distant areas of space, the sensitivity of radar equipment must ranges. A compromise can be achieved via a high-frequency be continuously optimized. Fraunhofer FHR relies on cooling window. The question of which material is best suited to such for this purpose: Helium is used to cool the radar receiver a window involves many different areas of expertise, from down to four degrees Kelvin or minus 269 degrees Celsius, high-frequency technology through mechanics and refrigera- four degrees above absolute zero. At these temperatures, the tion technology. Since cryogenic technology has not yet been atomic lattices hardly vibrate at all, so the inherent noise of the widely used in radar technology, Fraunhofer FHR is working receivers is also reduced. This could enable the sensitivity of closely with radio astronomers at the Max Planck Institute in radar systems to be doubled, based on theoretical calculations. Bonn and the CSIRO in Australia.

The helium coolant is conducted around a circuit. It is initially A first demonstrator has already been developed, and tests on compressed using a compressor – similar to the coolant in temperature and pressure stability carried out. Further steps a refrigerator – then fed to a cold head, which is placed in now include high-frequency measurements and determination a vacuum container. The helium is expanded again, in this of the system's noise figure. container, releasing its cold energy. Since the system is closed, the helium can hardly volatilize. There are some challenges to be overcome when building such a cryo-receiver. For one thing, a temperature difference of almost 300 degrees exists between the vacuum and the outside space – this thermal CONTACT radiation has to be intercepted. Furthermore, electrical cables Dipl.-Ing. (FH) Andreas Fröhlich must be fed in from the outside, and they cannot be allowed Phone +49 228 9435-769 to conduct any significant heat into the vacuum either. The [email protected]

39 BUSINESS UNIT SPACE

1 The TIRA space observation radar. 2 Cube-Sat: Thousands of satellites this size are currently orbiting the Earth. 3 Man-made objects that are orbiting the Earth – mostly space debris.

TIRA – SPACE OBSERVATION RADAR OF THE FUTURE

The situation in low-Earth space is changing dramatically: It is becoming fuller all the time and the satellites buzzing around are getting smaller and smaller. Space observation radars must keep pace with these developments, by meeting requirements such as higher resolutions and high sensitivity. Fraunhofer FHR's TIRA space observation radar provides an excellent basis for this and it is currently being prepared to fulfill future requirements.

The area where most people would assume there is only emp- For high-value satellites in particular, various demands, includ- ty space is becoming increasingly full. Driven by globalization, ing for mission support, are set to increase significantly in the digitalization, low-cost technologies and constant miniaturiza- coming years. Is some part of the satellites damaged? And if tion, countless satellites, both active and decommissioned, as so, which? With current systems, such questions will become well as an ever-increasing amount of space debris, are buzzing increasingly difficult to answer in the future. around in low-Earth space. In the past, the number of Earth satellites increased linearly, but now it is rising almost expo- Requirements for space observation systems nentially. While in the past only space agencies such as ESA and NASA launched satellites into space, Google and other As far as the choice of space observation systems for the companies are now increasingly entering the satellite business. future is concerned, radar is ideal. This is because it offers Another development is that satellites are becoming smaller several advantages over optical systems: Optical systems only and smaller, and their attachments ever more compact. After deliver results under cloudless skies and additionally depend all, small satellites are much cheaper and development times on the satellites, but not the sensor, being illuminated by the are shorter, making them easier to replace in the event of a sun. In contrast, active radar systems work equally efficiently failure. The smallest of these are the "cubesats", featuring the even under cloudy skies, in fog and haze, and day and night. smallest possible unit measures of just 11.35 x 10 x 10 centi- However, the demands on resolution are now enormous. meters. The following figure shows the scale of their footprint After all, even small satellites need to be recognizable on in space: In 2017, 18,000 cubesat launches were registered radar images, and not only as dots; in the future, it will for the subsequent five-year period. With such a flurry of also be possible to recognize details such as attachments or activity in LEO – the low-Earth orbit located between 200 and damage. However, this requires at least ten resolution cells per about 2,000 kilometers above the Earth's surface – orderly, object per spatial dimension. This means that for a satellite safe satellite operations are becoming increasingly difficult. As measuring 5 x 5 x 5 meters, the resolution would have to be a result, many satellite operators are already moving to higher at least 50 centimeters. altitudes. However, the further the satellites are from radar, the more difficult they are to detect and image.

40 1

2 3

TIRA is the only system in Europe to meet the basic In short, TIRA is the only system in Europe that fulfills these requirements basic requirements and that can therefore be expanded to form the space reconnaissance sensor of the future with The TIRA system already meets many of the basic require- relatively manageable effort. Fraunhofer FHR will meet this ments that a space observation system of the future needs. challenge in the coming years in order to significantly increase For example, it has two radar systems: A high-precision the information content of future TIRA radar images, thereby target-tracking radar that can track objects in space and an also enabling sufficiently good-quality imaging of small and imaging radar that produces high-resolution images supported distant space objects. by the target-tracking radar. A key core component of TIRA is its 34 m antenna, which ensures high sensitivity. This enables a lot of energy to be radiated into space towards an object in a targeted manner and as much as possible of the energy scattered back from that object to be recovered – the basic requirement for high sensitivity. All the necessary infrastructure is also in place, including high-precision mechanics that enable the radar antenna to precisely track the space objects passing by in the sky. Furthermore, the antenna is particularly CONTACT agile, which enables the tracking of space objects even when Dr. rer. nat. Jens Klare passing close to the zenith. Phone +49 228 9435-311 [email protected]

41 BUSINESS UNIT SECURITY

The attack on the World Trade Center on Sep- tember 11, 2001, led to numerous national and international research programs aimed at protecting civilians in peacetime.

Security research is based on three major pillars: Protecting people, protecting critical infrastructure, and protection against crime and terrorism.

Among all these pillars, radar offers numerous possibilities to increase security in the civilian area.

For example, combined with radar technology, drones can locate signs of life in people trapped in smoke-filled buildings or under rubble.

42 CIVIL SECURITY: WIDE-RANGING SUPPORT BY RADAR

On September 11, 2001, the attack on the World Trade already conducting research on this type of radar technology Center spread fear and terror throughout the world: After in a variety of directions. Cognitive radar goes even further, all, it was the first terrorist attack of this scale on a civilian with the radar system independently setting the optimal target. Further attacks followed in Madrid in 2004 and in parameters, fine-tuned to the current situation. London in 2005. Research responded: While previously there had not been any security research for the civilian sector, in Protecting critical infrastructure: Inspection robots the aftermath of the attack on the twin towers, numerous equipped with radar sensors national and international research programs were created to address the protection of the civilian population in times Civil security also includes discovering the smallest of cracks in of peace. One example for such a program is the German power plant cooling towers, tunnel systems, bridges, or similar federal government's security research program "Research for infrastructure. Drones and robots can take on these sometimes Civil Security", which is currently heading into its third round. dangerous but also time-consuming tasks. There are two In general, security research is based on three major pillars. starting points for radar technology here: On the one hand, First: The protection of people – whether at big events, train it can prevent collisions via sense and avoid. When the radar stations, or airports – as well as their rescue, for instance in sensor detects a wall or another obstacle, the data can be sent natural disasters, epidemics, attacks, or similar. Second: The to the drone's or the robot's control system to ensure that protection of critical infrastructure. This includes airports, train it avoids the obstacle. The Business Unit Security has already stations, waterways, and bridges as well as energy and water successfully completed the first tests. On the other hand, radar supply and communications. Third: The protection against sensors offer advantages for the analysis of infrastructures – crime and terrorism. For instance, how can we deal with the for example, they are capable of providing images exact to the fact that more and more people on the streets carry knives millimeter and detecting cracks and damages even in dark, and even use them in trivial disputes? There are about a dozen smoke-filled, or inaccessible environments. knife attacks per day in Berlin alone! Radar offers a number of ways to increase civil security for all three of these pillars and Protection against crime Fraunhofer FHR's Business Unit Security is a competent point of contact. Radar systems are also very useful for the third pillar, protection against crime. For example, they make it possible for Protecting and rescuing people: Unmanned systems with security forces to detect whether people are carrying knives or radar sensors other dangerous items underneath their clothing without the need for contact. In a disaster, it is often difficult or even impossible for the emergency forces to quickly get a precise picture of the situation. For instance, in the event of a fire it is extremely dangerous to enter a burning building to search for people. Drones combined with radar technology can help. Drones can fly into smoke-filled buildings and locate signs of life or animals using integrated radar sensors. At the same time, radar sensors can ensure that the drones navigate safely Contact: through buildings without hitting any obstacles. This way, Spokesman Business Unit Security rescue missions would be significantly faster, more efficient, and safer. Radar sensors can also provide valuable services M. Sc. when searching for buried people by locating signs of life YOUNGKYU KIM underneath the debris. In a next step, it would be conceivable Phone +49 160 2633 836 to let drones work autonomously – this would provide further [email protected] relief for human rescue workers. The Business Unit Security is

43 BUSINESS UNIT SECURITY

ORAS final presentation on the Institute's campus.

DRONE IN FLIGHT?

If a child is playing with a small drone in the back yard, this is not a problem. However, at political rallies or sporting events, the situation is different. In such cases, an oncoming drone can signal serious danger. The ORAS system reliably detects drones on approach, even if they are approaching through urban can- yons. The system's capabilities won onlookers over during its final presentation.

Unless appropriate security measures are in place, political flying in through a canyon of houses. In a second scenario, demonstrations can easily get out of hand, and political it approached at a higher altitude and was first detected by rallies and sporting events also need to be secured as well as the dome radar, this corresponds to flying above the roofs of possible. Emergency forces have to keep an eye not only on houses. In both scenarios, the camera panned to the drone. the people in the area, but increasingly on the airspace also. The test run was successful: The system's various applications This is because a drone could approach, for example, in order were vividly demonstrated. to disrupt political events or to display a banner or flag without authorization at sporting events. Fraunhofer FHR and various In addition to the final presentation, three other BMBF-funded partners have therefore joined forces in the ORAS project to projects with the same goal were presented alongside ORAS in develop a radar-based system for emergency services that Moosbach in October. In the decommissioned barracks, ORAS immediately detects drones. was able to optimally demonstrate its strengths – for example, when flying a drone through a canyon of houses below the Successful final presentation edge of the roof. The potential users from BOS and industry gave ORAS a positive report card, which is why FHR is striving The system managed to show what it is made of during the to further develop the system with a view to commercializa- final presentation. This was originally planned for April 2020 tion. in Moosbach, but due to pandemic restrictions it had to be relocated to the Fraunhofer FHR site and rescheduled to June 2020. To minimize the number of on-site attendees, the presentation was livestreamed to partners and potential end users. Fence radars were positioned on the site fence; the camera system and the dome radar were set up 200 meters further away. Controlled from outside, a drone performed CONTACT agile flight maneuvers over the FHR site: It zigzagged, flew up Dipl.-Ing. Andries Küter and down, moved close, then away again. In a first scenario, Phone +49 151 21416393 it flew over the fence radar and onto the site – equivalent to [email protected]

44 Emulator of the coastal radar transmitter (left) and the two antennas of the passive radar that will be mounted on the drones in the long term (right).

COASTLINES: WELL PROTECTED

External borders need to be adequately protected – including those of the European Union. In the Robor- der research project, a consortium is developing an integrated autonomous system that will help the EU secure its borders in the future. As part of the project, Fraunhofer FHR is to develop a passive radar which, when placed on drones, can increase the range of the coastal radar by up to 20 percent.

The European Union has a great interest in protecting its Increasing the range by up to 20 percent external borders against illegal immigration – for example at the Mediterranean Sea. How can this border protection be But what is the need for the passive receivers on the drones optimized? This question is being investigated in the Roborder if there is already coastal radar? Coastal radars are located EU consortium project by 26 partners from science and public on land, so they are relatively far away from vessels that are institutions including Fraunhofer FHR. The development goal heading toward the coast – possibly without permission. The is an integrated autonomous system that includes flying, coastal radar emits its waves, which are reflected by the vessel swimming, driving and diving drones as well as their mounted and then have to travel all the way back to the on-land radar sensors. unit. However, the further they have to travel, the weaker the signals become. The drones, on the other hand, swim or Fraunhofer FHR is concentrating on the passive radar which fly back and forth two to three kilometers offshore at a time, is to be incorporated into both the flying and floating drones. parallel to the coastline. The distance that the reflected signals While radar usually involves a transmitter on the radar unit have to cover to reach the antenna is therefore far shorter for emitting an electromagnetic signal and an antenna receiving the drones than the distance to the antennas on land. Accord- the echo reflected by the objects, in passive radar, the unit ing to theoretical calculations by Fraunhofer FHR, this extends itself does not transmit. Instead, it uses signals from other the radar's range by up to 20 percent – while maintaining the sources, such as radio or television signals. In the case of same probability of detection. The practical demonstration is Roborder, the system uses signals generated by a network of scheduled for spring 2021. It will be held jointly with the CNIT coastal radars. This coastal radar network is operated by one off the coast of the Italian province of Livorno. of the project partners – Italian research institute Consorzio Nazionale Interuniversitario per le Telecomunicazioni (CNIT). Like the passive radar receivers on the drones, it operates in the X-band, i.e. at approximately ten gigahertz. CONTACT Dr.-Ing. Diego Cristallini Phone +49 228 9435-585 [email protected]

45 BUSINESS UNIT TRAFFIC

Autonomous driving is a major future trend which, starting from the roads, is increasingly spreading to rail and sea transport as well as aviation.

Radar is the key sensor for more autonomy on road, rail, water and in the air. After all, the safety of all road users must be ensured at all times.

The Business Unit Traffic offers in-depth and broad-based scientific expertise in all aspects of radar, supplemented by industry knowledge. 46 RADAR SYSTEMS FOR INCREASED SAFETY IN CARS, ON AIRPLANES, TRAINS AND SHIPS

Cars that autonomously make their way through dense traffic ...on the water, in the air, and on rails while people comfortably lean back and read the paper – autonomous driving is a huge future trend in the traffic sector. At the moment, the Business Unit is heavily marked by appli- Spurred on by the automotive sector, the trend is increasingly cations in the automotive sector. But the level of autonomy expanding to encompass other modes of transport as well. is also increasing in other traffic areas – bringing about the Whether on the road, on rails, on the water, or in the air: associated requirements for the sensor technologies. For this Safety is essential for autonomous driving. The vehicles must reason, the Business Unit Traffic has also made significant be able to observe and assess the traffic around them to initi- contributions to the development of a number of radar ate the required responses – for instance to fully brake when a sensors for shipping and aviation. An example from shipping: child runs onto the street. Radar sensors are ideal for this task: The innovative sea rescue system SEERAD makes it possible Because, in contrast to optical sensors, they work day and to locate shipwrecked persons at a distance of six kilometers night and in any weather condition – even in dense fog. One with a transmission power of only 100 watts – a world record. could say: Radar is the key sensor for more autonomy on the In the aviation area, Fraunhofer FHR has developed a landing road, on rails, on the water, and in the air. assistance system for helicopters, among others. The system assists the pilot during the landing maneuver, when visibility is When it comes to radar, Fraunhofer FHR's Business Unit Traffic reduced by stirred up dust. offers deep and diversified expertise: From high frequency systems and signal processing to the classification of objects As far as the activities in railway traffic are concerned, the goal all the way to electromagnetic simulations. The business unit is to keep developing these in the future – because there are boasts high-quality cutting-edge technical equipment and a barely any solutions available in the market yet. The Business staff with in-depth physical knowledge. But there is more: The Unit Traffic wants to close this gap. There are numerous ap- staff members are also very well versed in the mobility industry plications for radar systems in railway traffic: For example, the and extremely familiar with current challenges and issues. sensors could analyze the track beds, detect cracks in tunnel Thus, in the Business Unit Traffic, even challenging problems walls, measure track widths, and address similar questions. can be resolved in a beneficial way and tailored individually to the customer.

On the road...

Nowadays radar sensors are installed in cars as a standard feature to support drivers. The Business Unit Traffic has already contributed its expertise in this area as well: Special radar antennas from Fraunhofer FHR have been installed 30 million times in 100 different vehicle types. Currently, particular focus is on the miniaturization of the systems as well as the development of conformal antennas – meaning antennas that adapt to the car's geometry for an optimal fit into the available constructed space. Further current research approaches in the Business Unit Traffic address the question of how radar waves Contact: interact with different materials. This is important, for exam- Spokesman Business Unit Traffic ple, when a radar sensor is to be installed behind a company logo or the bumper, while being invisible to the user. Newly Dr.-Ing. developed sensors are "put through their paces" in a test ANDREAS DANKLMAYER environment. Our simulation software GOPOSim allows for Phone +49 228 9435-350 the insertion of different moving objects such as cars, bikes, [email protected] pedestrians, and dogs into the different road scenarios.

47 BUSINESS UNIT TRAFFIC

1 Test measurement at Fraunhofer IIS: A person is detected by the radar before and after setting off, and the determined position is checked via an optically monitored marker on the helmet. 2 MIMO radar sensor developed at Fraunhofer FHR for motion detection. 3 Are any of the people on the road moving?

MORE SAFETY ON THE ROADS

Pedestrians, cyclists, streetcars, cars – traffic can become confusing at times. In the future, a new type of radar sensor system will be able to warn drivers in good time if somebody is steadily approaching their car. It was developed by Fraunhofer Institutes FHR, IIS and IVI. In a follow-up project, the system will be able to interpret entire street scenes via artificial intelligence, thus ensuring even greater safety.

People react quickly – but sometimes not quickly enough. For danger is detected at the very beginning of a movement, example, if a child runs across the road to catch a bus that and valuable, sometimes even life-saving time is gained. The has stopped on the opposite side, a car driver is very unlikely algorithms recognize an object as a person, set a marker and to be expecting this to happen – with potentially extremely determine the speed and direction in which the person is serious consequences. Although sensors can detect when moving. Are they moving toward the radar sensor and, hence, people or other objects are close to a vehicle and warn the toward the road? There is a fine line between triggering a driver, the warning would come too late in the case of a false alarm and failing to issue a warning in time, but the child running into the road. In the HORIS project, the FHR radar sensor can overcome this problem by taking around a Fraunhofer Institute in Wachtberg, IIS in Erlangen and the hundred measurements every second. Only when the person "Connected Mobility and Infrastructure" IVI Application is moving consistently towards the road at a certain minimum Center in Ingolstadt have set themselves the goal of improving speed over several measurements is an alarm triggered to road safety – particularly in situations involving large numbers warn the driver. of road users. Instead of a proximity warning as in the past, reliable behavior prediction is to be realized. This means that if The three institutes have divided the development tasks a child runs onto the road, the sensors should detect this at a in accordance with their competencies: Fraunhofer FHR is stage when the driver can still react and bring the car to a halt concentrating on the technological side and is developing before an accident happens. the algorithms, while Fraunhofer IVI is designing suitable test scenarios. Meanwhile, Fraunhofer IIS is taking care of the Speed not distance camera technology and motion detection and providing the measurement halls. In doing so, the Fraunhofer research team is building on existing technology from the automotive industry, using both Demonstration planned for spring 2021 the same radar chip technology and the same components for the sensors. The main development work lies in evaluating The project ran from May to December 2020. The demonstra- the data, i.e. in the algorithms. The highlight: While currently tor is ready: It can currently detect up to eight people at the installed sensors analyze how far a person is from the car, the same time and determine whether they are moving toward new system relies on measuring the speed. Thus, an imminent the road. It will measure a street scene in a test run at the

48 1

2 3

beginning of 2021. An overall test and a presentation for help prevent dangerous situations. In addition, the situational interested customers from industry is planned to take place in awareness feature is designed to increase accuracy and thus Ingolstadt in the second quarter of 2021. further reduce false alarms. And to further increase the safety of all road users in the long term. However, the collaboration between the three Fraunhofer Institutes is far from over. They plan to build on the HORIS results in a follow-up project which aims to further optimize the sensor, this time not just looking at whether someone is moving toward the road, but also taking account of the issues determining how and why they might make that move. As well as detecting that someone is approaching the car, the system will use artificial intelligence and an additional infrared camera to understand the overall situation. The aim here is to improve the system's reaction time. If, for example, a ball rolls into the road, a child may well follow it a few seconds later. If a bus stops, it is possible that someone will rush across the road to catch it. By detecting the whole situation rather CONTACT than just the movements of individual people, the system Dr.-Ing. Reinhold Herschel can save valuable extra seconds when warning the driver and Phone +49 228 9435-582 [email protected]

49 BUSINESS UNIT TRAFFIC

Scenario with ground truth trajectory, estimated trajectory and landmarks.

ACCURATE POSITIONING FOR SELF-DRIVING CARS

Is the car in the correct lane? How far away is the crosswalk? What a human driver usually estimates with a glance it can only be carried out by means of sophisticated sensors in self-driving cars. Fraunhofer FHR has now investigated what radar sensors are able to do in this regard. The result: They can be used to determine the car’s position to within a few centimeters.

If cars are to self-drive through roads and streets in the future, without causing accidents, and to do this, they need to record this will require a number of basic technologies. Among other their surroundings in great detail. tasks, the vehicle must be able to determine its position to within a few centimeters and, if necessary, create a map of its Since radar data is too large to evaluate each individual point, surroundings. This is also known as Simultaneous Localization data belonging to one object is combined. This process is as- and Mapping (SLAM) and it is particularly necessary in sisted by boundary frames created using sensor data from the areas where the GPS signal is not accurate enough or the camera and LiDAR. For example, if a bounding box is created surroundings are unknown and no map material is available. for a car, all radar data within that box will be clustered. The The environment can usually be measured with three types of work regarding SLAM shows: While self-location techniques sensors: Optical cameras, LiDAR and radar. Optical cameras that use only radar data and known landmarks allow for only work in bright light and with reasonably good visibility. higher positioning accuracies, SLAM techniques also permit LiDAR systems are bulky and expensive, and their results are to simultaneously generate a map with radar data when no not very reliable in poor weather conditions. Radar systems other sensor data is available. The position of the car can be offer an alternative: They provide reliable results even in fog, determined up to 20-30 centimeters accuracy. heavy rain and darkness.

Investigation based on real test data

Can this kind of self-positioning be achieved in a car using radar sensors? This was investigated at Fraunhofer FHR. The utilized test data came from nuScenes, a large-scale public dataset for autonomous driving. This includes both radar and LiDAR data, as well as data from optical cameras. The CONTACT framework originates from the field of robotics – after all, Dr. rer. nat. María A. González-Huici robots too have to be able to move in their environment Phone +49 228 9435-708 [email protected]

50 Simulated RCS (Radar Cross Section) of a Golf III model.

TIME-DYNAMIC RADAR SIMULATION OF TRAFFIC SCENARIOS IN REAL TIME

Up to now, developing new driver assistance systems has required numerous test drives. After all, the decision algorithms have to be trained accordingly. Fraunhofer FHR has now developed a simulation tool that generates raw radar data and electromagnetically simulates time-dynamic processes – based on physical optics and, depending on the complexity, in real time. It is therefore ideally suited to replacing time-consuming test drives.

Driver assistance systems make it easier for drivers to maintain superimposed onto an object – for example, the movement an overview and thus ensure greater safety. This requires of the arms and legs of a running pedestrian, where the limbs environmental sensors that reliably "keep an eye" on the move independently of the pedestrian themselves. Through car's surroundings, as well as algorithms that evaluate this appropriate algorithms, such micro-Doppler signatures can be data and make the necessary decisions with regard to safety. used to carry out classifications that can enable the identifi- Up to now, these algorithms have mainly been tested and cation of a pedestrian, cyclist, or a vehicle. The simulation is trained on real test drives – a time-consuming and expensive based on a deterministic ray tracing method as well as physical undertaking. optics in calculating the scattering on the objects. Unlike the shooting and bouncing rays algorithm, in which a fixed Fast simulations instead of lengthy test drives number of rays are sent into space, GOPOSim only emits rays that are known to hit objects into space – this is referred to as Fraunhofer FHR's GOPOSim tool can be used to generate raw an analytical approach. The decisive advantage: The simulation data for testing the algorithms – thus replacing test drives. An time can be significantly reduced. Plus, depending on the additional special feature: It can also be used for time-dynamic complexity, simulations are already possible in real time. This is processes, such as those that occur everywhere in traffic a prerequisite for software in the loop or hardware in the loop scenarios, for example when a cyclist from a side street crosses simulations. the lane without looking. The simulation tool is already being used in various projects with customers from industry. The results can also be processed as an object list and used in the ATRIUM radar target simulator, which can be used to test radar sensors over the air. CONTACT The software can be used to create raw data suitable for eval- M. Eng. Stefan Wald uating micro-Doppler effects on moving objects in the scene. Phone +49 228 9435-771 These occur when multiple larger and smaller movements are [email protected]

51 BUSINESS UNIT TRAFFIC

Synthetic model of a track bed (left) next to Experimental model (right) including GPR sensor.

EARLY DETECTION OF TRACK BED DAMAGE USING RADAR

During incessant rains, for example the monsoon, even sophisticated track beds have little chance of draining the water. This results in undercutting and holes, which can in turn lead to serious accidents. Using a ground-penetrating radar system, such undercutting can be detected in good time along the entire length of the track in a contactless process.

Track beds essentially consist of three different layers: The This enables the acquisition of high-resolution radar images, ballast bed, also known as bedding, the subgrade protection which can be used to examine small structures within the track layer and the substructure or subgrade. The function of the ballast. structures is to distribute the weight of the train evenly over the ground and to allow rainwater to run off. However, the The main challenge lies in evaluating the collected data: Where ravages of time gnaw away at the track beds: Some ballast in the track bed is there damage? A sophisticated system stones crack due to the pressure of the trains, and the track made up of real-life tests, simulations and machine learning bed also widens and becomes shallower over the years. The helps with this. In a track bed model, cavities within the track main problem is too much rain, for example in monsoon areas, bed were firstly modeled under various conditions such as or melt water in mountainous regions: The water can wash ballast contamination and aging, then measured using ground out the ballast bed and substructure and tear holes in them, penetrating radar. These real-world results were used to which can in turn lead to serious accidents. However, verifying improve the simulation model. The simulation results, in turn, these signs of wear and tear has hardly been possible up to created the huge database needed to train the machine learn- now. The current possibilities are visual inspection and digging ing. Generating this database using trackbed models alone a hole to check the structure at random intervals. would take several years, whereas simulating the required data requires only a fraction of the time. The simulation model is Non-destructive analysis of the entire track bed ready, and one company has already expressed interest.

Together with RWTH Aachen University, Fraunhofer FHR has now developed a GPR (Ground Penetrating Radar) system that can be used to examine the track beds non-destructively and over their entire length. To do this, the radar system must be mounted on a mobile platform that can travel along the track CONTACT and examine it. The system can detect holes down to a depth Dr.-Ing. Fernando Rial Villar of about one meter, which is more than adequate for a normal Phone +49 228 9435-770 track bed depth. The spatial resolution is one centimeter. [email protected]

52 To determine the material parameters, transmission and reflection of nearly plane electromagnetic waves are measured first.

PRECISE MATERIAL CHARACTERIZATION

Vehicles come with numerous in-built sensors that scan the environment and provide valuable data for driving assistance. It is therefore important for vehicle manufacturers to know how the vehicle's parts change the electromagnetic signals that the sensors emit and receive. Fraunhofer FHR carries out such analyses precisely and, in addition to the results, is now calculating information on the measurement accuracy for the first time.

Without a driver, the vehicle meanders through the streets determined for this purpose. One parameter is the dielectric while the occupants stick their noses in books or look at constant, which is an indication of how the material interacts their smartphones – at least that is the long-term vision of with the electric field of the wave. The second is the loss autonomous driving. It is essential that the cars are able to factor, which describes the attenuation experienced by the recognize their surroundings at all times and correctly assess wave when it interacts with the material. dangers. This is the task of driver assistance systems, which are being installed in vehicles more and more often. The envi- ...with measurement inaccuracies and standard deviations ronment recognition is based on numerous different sensors: Integrated into the car, they detect obstacles on the road Plus, a new point: In the future, besides the measurement and pass on their data to the vehicle control system, which results they received before, customers will also receive an in- can, for example, initiate a braking maneuver in the event of dication of the measurement inaccuracies – more precisely, the imminent danger. Radar sensors use electromagnetic waves to distribution of the measurement results as well as the standard perceive their environment. These waves have to propagate deviation. This means that they will be able to accurately not only through the air until they hit a potential obstacle, but assess the measurement inaccuracy that is occurring, and the also through the car parts behind which the radar is installed. results will be even more concrete and meaningful for them Manufacturers therefore want to know for example: How do than they were before. They will even be able to combine the the vehicle materials, including the various layers of paint, different measurements from several laboratories to get the affect the electromagnetic waves? What is the effect of the best possible estimate of the parameters of a material and various painting processes? their measurement uncertainties. In addition, Fraunhofer FHR has identified elements in the measurement setup that can Analyses... be used to further optimize the measurement accuracy in a further step. Fraunhofer FHR is carrying out corresponding investigations for numerous customers. The measuring equipment can CONTACT be used to professionally measure and characterize various Dr.-Ing. Thomas Bertuch material types – even those consisting of several different Phone +49 228 9435-561 homogeneous layers. Two electromagnetic parameters are [email protected]

53 BUSINESS UNIT PRODUCTION

Radar sensors can also monitor production processes where optical systems reach their limits, for example, in rolling mills where very high temperatures prevail and a lot of steam and slag is generated.

Radar sensors additionally enable non-destructive product inspection – be it in food inspection, plastic components of all kinds or composite materials.

The Business Unit Production offers the necessary expertise as well as the technical equipment to turn individual inquiries from industry partners into a success. 54 PRODUCTION PROCESSES ALWAYS IN VIEW

When something goes wrong in industrial production process- along the value chain, each additional production step costs es, this will very quickly lead to high costs. Thus, companies hard cash. Panels designated to be made into car doors are have a major interest in monitoring production processes. also frequently checked visually for defects. A millimeter wave While some questions can be satisfactorily addressed using sensor allows for the reliable detection of even the smallest of camera and laser systems, other production processes require scratches. In the long run, this could even provide 100 percent sensors with capacities that go beyond those of optical control. systems. Radar sensors offer an ideal solution here: They are not only capable of measuring under difficult environmental Looking to the future: Smart factories and additive conditions, for instance with limited visibility, but also of look- manufacturing ing through dielectric materials to detect defects. Fraunhofer FHR's Business Unit Production offers the necessary expertise What will production look like in the future? One possible for all questions relating to radar. vision is the smart factory, where the supply of components and production are run intelligently and autonomously. How- Non-destructive testing for food, plastics and compos- ever, autonomy always starts with the sensors: This is where ites the Business Unit Production offers the required expertise as well as the capabilities to develop individual solutions for Sometimes, it makes sense to not only check the products safety-critical aspects such as machine safety. surface, like for car doors, but to also have a look inside – without destroying the objects. Radar makes this possible as Additive manufacturing, in which components are produced well, at least for dielectric materials. One of the applications in 3D printers, is another future trend. For example, this allows is food testing: This involves detecting foreign matter that has antennas to be printed or component concepts to be realized accidentally gotten into the food in the production process. that could not be produced in this way before. Together with high-frequency technology, additive manufacturing opens up Radar is also a promising solution for non-destructive testing numerous new fields of application: For example, the anten- of additively manufactured components, i.e. 3D printed nas could be integrated directly into functional components of plastics. In addition, radar examinations offer benefits during the production machine by making the component function the lifespan of a product, for instance for composite materials like an antenna at the point where it is penetrated by the like the ones used for the rotor blades of wind turbines. FHR radar wave. is developing imaging algorithms for high-resolution millimeter-wave radar scans at 60 GHz for this purpose. One of the areas in which this work is being carried out is the FiberRadar project, funded by the EFRE Leitmarkt-Agentur.NRW. These are used to monitor fiber optic systems in fiber composite production. Promising results have already been achieved here using FHR's broadband radar technology at 80 and 220 GHz. FHR's fully integrated SiGe chip solution at 220 GHz can achieve high image resolution, making both fiber layers and material defects clearly visible. Greater penetration depths can be reached by fusing multiple frequency bands. Contact: Checking production processes for metals Spokesman Business Unit Production

One interesting field of application for radar systems are rolling mills in the steel industry. In general, the following applies DANIEL BEHRENDT to production processes: The earlier defects are detected, the Phone +49 151 120 101 64 cheaper it is to correct them. For example, if a car door has a [email protected] dent, it can be easily sorted out in the beginning. But further

55 BUSINESS UNIT PRODUCTION

1 Radar width measurement on the roughing stand of Salzgitter Flachstahl GmbH. 2 STRIKE sensor integrated into the IMS thickness gauge. 3 Measuring bracket of IMS Messysteme GmbH's thickness measuring system.

USING RADAR TO CHECK STEEL SHEET THICKNESS

When steel strips are being rolled, they have to be checked to make sure they have the desired thickness. In applications where adverse environmental conditions such as steam, scale and spray water prevail, this has previously only been possible with ionizing isotope or X-ray technology. In contrast, a novel radar system measures the thickness of various materials in the submillimeter range even under adverse conditions – and even without ionizing radiation.

Be it for cars or component cladding, steel is often processed The STRIKE sensor delivers reliable results even under in the form of strips. To this end, the slabs of raw material adverse environmental conditions are rolled out step-by-step into long strips in rolling mills and rolled into coils for transport. An elementary feature of the The Strike sensor developed at Fraunhofer FHR has already rolling process is that the strip produced must be of the spec- been integrated into a thickness measurement system at IMS. ified thickness over its entire length, which should not have Environments where there is vapor, mist and dust and which any major fluctuations. Strip or sheet thickness is currently are aggressive allows the material thickness to be measured measured mainly using systems based on isotope and X-ray reliably and accurately. The measuring system consists of two radiation. However, this adds to the costs; after all, it requires four-channel radar sensors mounted opposite each other in a radiation protection measures. Moreover, these systems reach C-frame. The two sensors emit radar beams that are reflected their limits when the material is very thick. Then again, optical by the material passing through and received again by the systems are sensitive to water vapor and fog. sensor. Since this happens simultaneously from below and above, the distance values can be calculated from reference In collaboration with IMS Messsysteme GmbH, Fraunhofer calibration data, which allows the strip's thickness to be FHR has therefore developed the first thickness measurement determined. One challenge is that the steel strip is constantly system based on radar sensor technology for hot rolling and moving under the sensors at a speed of up to 20 km/h. This heavy plate mills. The advantages: Radar systems require only must be matched by the measurement rate and the measure- low transmission power, so no additional safety measures ments on the top and bottom must be synchronous – this is are necessary. Unlike optical systems, they are not sensitive the only way to achieve highly accurate material thickness to harsh environmental conditions such as fog, spray water measurements continuously. The developed STRIKE sensor and dust. At the same time, radar systems require hardly any ensures this: It currently operates at a measurement rate of maintenance. The electronics are maintenance-free; only the one kilohertz. The entire measuring system thus delivers eight sensor's viewing window must be kept free from dirt, scale times 1000 synchronously recorded distance measurement and rolling emulsion. values per second.

56 1

2 3

The evaluation unit is based on FPGAs (Field-programmable The sensor is ready. It is currently in the test phase so Gate Arrays). It is integrated directly into the sensor and allows as to guarantee reliability. Once this is completed, IMS fully edge-supported evaluation. The entire signal processing Messsysteme GmbH will integrate the sensors into its setup of the radar signals takes place on the FPGA – even the and deliver its first measuring system to a U.S. rolling mill. control of the radar chips and the communication with IMS Of course, the sensor's application is by no means limited Messsysteme GmbH's central computing unit was implement- to rolling mills. Indeed, it can be used wherever there is a ed in this integrated logic unit. Thus, the thickness of the steel need to determine distances and angles. sheet can be measured in real time at a rate of one kilohertz.

The accuracy of the thickness measurement is below 100 micrometers for a flat running strip. If the strip surface is inclined, for example due to the strip movement or corruga- tion, the angular deflections are determined and corrected by means of the quad arrangement. The accuracy of the thickness measurement can thus be kept below +-150µm. With the antenna geometry used, the measurement range of CONTACT the strip's possible angular positions is up to 3 degrees in each Sabine Gütgemann direction. Phone +49 160 966 519 27 [email protected]

57 BUSINESS UNIT HUMAN AND ENVIRONMENT

Radar systems are becoming increasingly smaller and less expensive, bringing them much closer to people.

One of the possibilities here is that radar can determine peoples’ breathing and pulse rates through clothing – whether in the medical field, fitness or elderly care.

Radar also enables contactless man-machine communication in environments where optical systems reach their limits.

It also offers many advantages in the environmental field, for example in increasing efficiency in agriculture.

The Business Unit Human and Environment offers the necessary expertise in all these areas.

58 RADAR: FOR HUMAN AND ENVIRONMENT

Radar technology is becoming ever smaller and cheaper – now expertise to respond to this trend and to provide companies reaching a degree of miniaturization that brings it closer to with customized support. humans. But where does it make sense to the use of radar in relation to humans? Generally, everywhere where geometric Radar for the environment and kinematic values are measured, i.e. where the shape and the movement of an object are to be analyzed. The term precision farming refers to increasing the efficiency in agriculture using modern technology. Radar sensors are an Radar for humans ideal fit for this task: It is harmless for people, animals, and plants and can provide not only images of leaves and stems, One example is checking the vital signs, i.e. breathing and but also the possibility of examining roots, thus enabling the pulse rate. In this case, radar is used to measure the plant-penetrating analyses. In addition, animals are also movement of the chest to conclude the breathing rate, coming into focus: the detection of wild animals and the vital while the pulse rate is deducted from the movement of the parameter monitoring of stable animals is another exciting skin – and similar to the scanners at the airport, this can be field in which radar technology can open up new possibilities. done through the clothing. One area where this is useful is for newborns in hospitals. Further applications are possible in the In the course of climate change, the importance of weather areas of care for the elderly, sleep laboratories, or even fitness. radar and the weather forecasts bases on it is increasing as As far as the signal processing is concerned, a lot of research well. While these are established technologies, there is still work is still required in this attractive field. As one of Europe's a lot of need for improvement. Here too, the Business Unit leading radar institute, Fraunhofer FHR is optimally positioned Human and Environment is pursing many ideas – because the for these challenges. technological advances that were achieved in the field of radar can also be used for weather radar. Radar is also well-suited for other questions involving man, such as movement analysis, be it for gait analysis in sports or The environment area also includes a flashing red warning in rehab. For example, together with partners, the staff in the light fitted to wind turbines to warn aircraft pilots. In many Business Unit Human and Environment conduct research on regions, however, aircraft are the exception. The ParaSol radar the question of how relieving postures can be detected after developed in the Business Unit Human and Environment an accident. recognizes approaching aircraft, allowing the flashing light to be turned on only when needed. The system has already been Radar for communications approved by German Air Traffic Control.

It is not only in the medical environment where radar has a lot to offer, but also in the area of communications. One field of interest is human-machine interaction. For example, many new generation smartphones are already equipped with an integrated radar sensor. The advantage: The sensor recognizes gestures even through clothing. Thus, a user can answer a call with a gesture without having to take the phone out of Contact: her jacket pocket. Gesture recognition via radar also makes Spokesman Business Unit sense in the area of occupational safety. Thus, you no longer Human & Environment need to press small buttons with thick work gloves and can instead control the machines with gestures and hand signals. Prof. Dr. rer. nat This especially makes sense in areas where textile-penetrating JENS BONGARTZ gestures are appropriate or where the working environment Phone +49 2642 932-427 contains a lot of vapor and steam, for example. The Business [email protected] Unit Human and Environment is optimally positioned with its

59 BUSINESS UNIT HUMAN AND ENVIRONMENT

1 Sample MRI images showing a homogeneous phantom (right) and a kiwi (left) with and without metamaterial plate. The signal-to-noise ratio (SNR) in the marked area (ROI) is indicated in each case. For the phantom measurements (with TR=100 ms), the slice shown is oriented perpendicular to the metamaterial plate, whereas for the measurement with the Kiwi (TR=1 s), the slice is parallel to it. 2 The smart metamaterial plate (manufactured at Fraunhofer FHR) in use in the MR scanner at Fraunhofer MEVIS. 3 The innovative sheath current barrier allows the use of other diagnostic tools under the extreme conditions in the MRI.

METAMATERIALS OPTIMIZE MAGNETIC RESONANCE IMAGING

Magnetic Resonance Imaging (MRI) has to date been difficult to combine with other diagnostic methods. This is because the strong high-frequency fields in MRI induce sheath currents on the cables of added devices. Now, MRI-compatible, compact sheath current suppressors based on metamaterial technology from Fraunhofer FHR significantly simplify this. Furthermore, smart metamaterial plates result in a far higher signal-to-noise ratio in MRI: The detection of fine structures is significantly enhanced.

MRI has become an indispensable part of medical diagnostics. practical solution to this problem in an internal project. Either Among other things, it allows the brain and spinal cord, as sheath current suppressors are attached only at some points of well as internal organs, muscles and joints to be imaged layer the cable, or the entire cable is covered with a mantle formed by layer and examined non-invasively. But sometimes making by a multitude of sheath current suppressors. The technology, a correct diagnosis is not enough – a combination of different which is currently being patented, is based on metamaterial diagnostic procedures is required. However, this presents technology. These are not materials in the usual sense, but challenges: The MRI's strong high-frequency fields induced into artificial entities that have been given a special structure and the cables of additional devices, be they ultrasound equipment, behavior. Since MRI scanners operate at various frequencies monitors or similar devices, can interfere with the measure- depending on the design and manufacturer, various sheath ments. Heat can also be generated at the cables’ shields by current suppressors designs have been developed: For 1.5, the induced currents to the point that they can cause burns 3 and 7 Tesla devices. The sheath current suppressors are in patients. Therefore, it is essential to suppress the induced compact, tunable and reusable. They also preserve the cable's sheath currents. This is typically done using current chokes. flexible properties. They can be detached from one cable and These are based on winding up the leads in order to realize the attached to another. Furthermore, the cables can be equipped highest possible impedance for the sheath currents. However, with several different sheath current suppressors at the same this approach is too bulky and requires more space and long time allowing for multiple frequencies and broad bandwidth leads. Other solutions are based on ferrite beads that can be use. For example, a sheath current suppressor solution for 1.5, attached to the respective cable by means, e.g. of a snap lock. 3 as well as for 7 Tesla can be attached to the same cable. Nevertheless, due to the magnetic nature of such components, they are not suitable for use in MRI. Various sheath current barriers have already been characterized in Fraunhofer MEVIS’ research MRI scanner and their function- Sheath current suppressors for MRI ality has been successfully proven. Fraunhofer FHR also has at its disposal appropriate on-bench measurement equipment, Together with the Fraunhofer Institute for Digital Medicine including two coils with which the sheath currents can be MEVIS, Fraunhofer FHR has now developed a convenient and specifically generated and measured. Up to now, the sheath

60 1

METAMATERIALS OPTIMIZE MAGNETIC RESONANCE IMAGING

2 3

current barriers have been manufactured using conventional leap in measurement efficiency is enabled by smart metama- production methods. However, new manufacturing technolo- terial plates, which are placed on the part of the body to be gies are now being used such as 3D printing technology, i.e. examined during the MRI scan. Various metasurface plates have additive manufacturing, which is also possible at Fraunhofer already been tested in the Fraunhofer MEVIS MRI research lab FHR. This provides a cost-effective and at the same time and their enhancing effect has been successfully demonstrated. high-performance solution.

Metamaterials improve measurement sensitivity by a factor of five

Metamaterial devices also offer many advantages and opportunities in improving MRI images themselves. Among other things, they can significantly improve measurement efficiency: CONTACT If the scan is carried out using surface coils placed close to the Dr. Endri Stoja patient's body, the signal-to-noise ratio (SNR) can be improved Phone +49 228 9435-701 by up to 20 percent, depending on the region to be imaged. If [email protected] the coils permanently installed in the MRI scanner, the so-called body coils, are used, the SNR can be increased as much as Dr. Diego Betancourt fivefold. Fine structures are thus much more easily-identifiable Phone +49 228 9435-370 on the images as the contrast increases considerably. This great [email protected]

61 BUSINESS UNIT HUMAN AND ENVIRONMENT

Monitoring system for the contactless recording of vital parameters.

COVID PATIENTS’ CONDITION ALWAYS IN VIEW

Only a small proportion of covid patients are in intensive care. For all of them, however, the question arises: Is their condition deteriorating? A sensor system being developed by various Fraunhofer institutes in the M3-Infekt consortium project is designed to detect such a deterioration at an early stage – using, among other things, a MIMO radar that analyzes the breathing rate without contact.

Is the covid patient's condition deteriorating? This question MIMO radar sensor measures breathing rate arises not only in intensive care units, where they are monitored very closely, but also in other hospital wards and Fraunhofer FHR is contributing a contactless MIMO radar sen- in home care. A modular, multi-modal and mobile sensor sor. This can be installed in the corner of a room, for example. system called M3-Infekt will in the future be able to keep a From here, it determines the breathing frequencies of the constant eye on the condition of those infected and detect people who are in the sensor's wide field of view. The chest deterioration at an early stage. Fraunhofer FHR is part of movements caused by breathing can be detected by radar a consortium consisting of 10 Fraunhofer institutes. In the even through bed covers. The sensor design used here allows future, the developed sensor system will not only monitor the signals from different people to be isolated. If a patient's health status of COVID-19 patients, but will also be used in basic breathing rate changes, this can be an indication of a those infected by other infectious diseases. deteriorating condition. In addition to the radar sensor, there is another non-contact sensor: A hyperspectral image sensor Different sensors work together from Fraunhofer IIS/ENAS. Its results can help factor out multiple reflections and the resulting ghost targets of the MIMO The sensor system consists of different sensor groups that radar. The sensors should be built up to the point where they complement each other. Wearable sensors that can be worn can be used for initial subject studies by mid-September 2021. on the body constitute one of these groups. A textile-integrated sensor records ECG data, a sensor wristband records body temperature, pulse and blood oxygen saturation, and another textile sensor records the ventilation situation of the lungs. Also part of the project is energy harvesting, where concepts and solutions are being developed on how these wearable sensors can be powered by mechanical movement. CONTACT M. Sc. Sven Leuchs Phone +49 160 6840822 [email protected]

62 Concept rendering model, front.

COVID PATIENTS’ CONDITION ALWAYS SHORT-RANGE WEATHER RADARS FOR IN VIEW OPTIMIZED FORECASTING

Currently, weather forecasts are mostly based on long-range radars. However, long-range weather sensing brings intrinsic limitations: Due to the curvature of the Earth, about 70% of the troposphere below one kilometer cannot be observed, and the temporal and spatial resolutions are also quite coarse. Conversely, short- range weather radars in development at Fraunhofer FHR can potentially sense the lower troposphere and dramatically improve spatial and temporal resolutions.

Rain, hail, storms, sunshine: The weather is part of our lives. of the lower troposphere. Moreover, electronic beam steering Although the forecasts in Germany are generally good, there in elevation enables much faster sounding of the hemisphere. are often heavy rain events, flash floods or storms that hit Indeed, a volumetric scan by electronic means only takes one entire regions completely unprepared. In addition, many minute, thereby improving the temporal resolution respect to countries in the World cannot afford reliable and localized long-range radars by a factor five. Fraunhofer FHR is being weather forecasting. developing such technology demonstrator within a weather radar initiative aiming at advancing radar meteorology in Weather monitoring is usually based on mechanically rotating Central Europe. To this end, a Memorandum of Understanding long-range weather radars covering a range of about 250 has been signed and finalized with the Meteorological Institute kilometers. The emitted radar beams directed at lower altitudes of the Rheinische Friedrich-Wilhelms University in Bonn and the bend only moderately towards the Earth's surface. Therefore, Delft University of Technology in the Netherlands. a widening gap to the surface quickly develops as the distance from the sensor increases. For this reason, nowadays, about A flat-panel micro weather radar is prospected to be installed 70 % of the troposphere below one kilometer cannot be ob- on the roof of Fraunhofer FHR in Villip and deliver initial results served by radar means. Moreover, long-range radars demand by the end of 2021. Plans for industrialization of the prototype for high ownership costs, around several millions Euro, and together with the German and European industry are under require about five minutes to complete a volumetric sampling evaluation. To this respect, one key condition is well kept on of the hemisphere, a time interval often too coarse to timely the foreground: The system should be commercialized at a capture important weather events. comparatively inexpensive price point around 100 K€, finally opening new possibilities for next-generation weather sensing. Better temporal and spatial resolution

A network of micro-radars could overcome these disadvan- CONTACT tages and improve the accuracy of weather forecasts. At the Dr. Stefano Turso comparatively shorter range of 50 kilometers, the curvature Phone +49 176 353 397 02 of the Earth plays a negligible role, finally allowing full sensing [email protected]

63 ANNEX

EDUCATION AND TRAINING

Lectures

WS 2019/2020

Bertuch, Thomas: "An- Heberling, Dirk: "Hoch- Pohl, Nils: "Bachelor-Ver- tennen und Ausbreitung", frequenztechnisches Prakti- tiefungspraktikum Elektron- Fachhochschule Aachen kum", Rheinisch-Westfälische ik", Ruhr-Universität Bochum Technische Hochschule Brüggenwirth, Stefan: Aachen Pohl, Nils: "Elektronik "Kognitive Sensorik", 1 - Bauelemente", Ruhr-Uni- Ruhr-Universität Bochum Heberling, Dirk: "Moderne versität Bochum Kommunikationstechnik - Cerutti-Maori, Delphine: EMV für Mensch und Gerät", Pohl, Nils: "Grundlagenprak- "Radar Systems and Rheinisch-Westfälische Tech- tikum ETIT", Ruhr-Universität Measurements", Technische nische Hochschule Aachen Bochum Universität Braunschweig Knott, Peter: "Antenna Pohl, Nils: "Integrierte Hoch- Cerutti-Maori, Delphine: Design for Radar Systems frequenzschaltungen für die "Signal Processing for (VO)", Rheinisch-Westfälische Mess- und Kommunikation- Radar and Imaging Radar", Technische Hochschule stechnik", Ruhr-Universität Rheinisch-Westfälische Tech- Aachen Bochum nische Hochschule Aachen Knott, Peter: "Antenna Pohl, Nils: "Master-Prakti- Heberling, Dirk: "High Design for Radar Systems kum Schaltungsdesign inte- Frequency Technology - (UE)", Rheinisch-Westfälische grierter Hochfrequenzschal- Passive RF Components", Technische Hochschule tungen mit CADENCE", Rheinisch-Westfälische Tech- Aachen Ruhr-Universität Bochum nische Hochschule Aachen Krebs, Christian: "Leiter- plattendesign", Hochschule Koblenz

64 SS 2020

Brüggenwirth, Stefan: Heberling, Dirk: "Hoch- Stanko, Stephan: "Radar "Grundlagen der Radartech- frequenztechnisches Prakti- in der Medizintechnik", nik", Universität der kum", Rheinisch-Westfälische Hochschule Koblenz Bundeswehr München Technische Hochschule Aachen Caris, Michael: "Radar in der Medizintechnik", Hochschule Knott, Peter: "Radar Koblenz Systems Design and Appli- cations", Rheinisch-West- Ender, Joachim: "Radar fälische Technische - Techniques and Signal Pro- Hochschule Aachen cessing", Universität Siegen Krebs, Christian: "Leiter- Heberling, Dirk: "Elek- plattendesign", Hochschule tromagnetische Felder in Koblenz IK (ehemals EMF 2 IK)", Rheinisch-Westfälische Tech- Pohl, Nils: "Master-Prakti- nische Hochschule Aachen kum Schaltungsdesign inte- grierter Hochfrequenzschal- Heberling, Dirk: "High tungen mit CADENCE", Frequency Technology - Ruhr-Universität Bochum Antennas and Wave Propaga- tion", Rheinisch-Westfälische Pohl, Nils: "Integrierte Technische Hochschule Digitalschaltungen", Aachen Ruhr-Universität Bochum

65 ANNEX

Supervised doctoral Supervised master theses studies

Giovanneschi, Fabio: "On- Arumugam, Ram Kishore: Radarsignalen", Hochschule Transmit Modules of a Ra- line dictionary learning for "Development of super-res- Bonn-Rhein-Sieg dar", Ernst-Abbe-Hochschule classification of antipersonnel olution detection algorithms Jena landmines using ground pen- for sparse scenes in presence Galleguillos Loza, Pablo etrating radar", Universität of clutter", Technische Ernesto: "Vitalparame- Chaudhury, Nandan Dutta: Siegen Hochschule Ingolstadt termessung bei Nutztieren "An investigation on the mithilfe eines zweikanaligen possibility for bandwidth Krämer, Patrick: "Studies Awadhiya, Rajat: 94GHz FMCW-Radars", improvement of dielectric of Higher Order Mode "Increasing the coherent in- Hochschule Bonn-Rhein-Sieg antennas via modification Couplers for the Upgraded tegration time for space sur- of their geometry", KTH Travelling Wave Acceleration veillance radar operations", Jung, Marie: "Kontaktlose Royal Institute of Technology, System in the CERN SPS", Rheinisch-Westfälische Blutdruckmessung mithilfe Schweden Rheinisch-Westfälische Tech- Technische Hochschule eines CW-Radars anhand von nische Hochschule Aachen Aachen Modellen des maschinellen Oevuenc Kaya, Sertac: Lernens", Hochschule Trier "Baseband Receiver Marquardt, Pascal: "Adap- Bauer, Alexander: Opimization for NR mmWave tive Spectral Least-Square "Micro-Doppler Based Limb Langmesser, Florian: Mobile Radio Testing", Techniques for Reaction-Dif- Detection For Gait Analysis", "Design and Implementation Rheinisch-Westfälische Tech- fusion Equations", Universität Hochschule Koblenz of a Low-Power Narrow-Band nische Hochschule Aachen Duisburg-Essen Radar Transmitter at X-Band", Cetin, Zuhal: "Design Fachhochschule Aachen Ramesh, Avinash Nittur: Wasserzier, Christoph: und Realisierung eines "SLAM with RADAR in "Noise Radar on Moving D-Band Verstärkers in einer Liebelt, Lukas: "Entwicklung Automotive Applications", Platforms", Tor Vergata SiGe-BiCMOS Technologie", eines synchronisierbaren, Universität Siegen University of Rome, Italien Ruhr-Universität Bochum kohärenten Frequenzkonvert- ers auf Basis der direkten dig- Schneider, Moritz: "Devel- Esser, Niclas Alexander: italen Synthese", Technische opment and Construction "Konzeptionierung und Hochschule Bingen of the Mechanics for a Programmierung eines 16-Element Phased-Array Systems zur echtzeitfähigen Nalkay, Rahul: "Design of a Radar to Analyse Fragment- Datenaufzeichnung, Verarbe- carrier platform and Analysis ing Objects in Earth Orbit", itung und Visualisierung von of a Cooling High-Power Rheinisch-Westfälische Tech-

66 nische Hochschule Aachen dar Applications at X-Band", Wallrath, Patrick: Fachhochschule Aachen "Verfahren zur Bestimmung Schneuing, Arne: der Eigenbewegung eines "Reconstruction of Spenrath, Florian: "De- MIMO-Radars unter Ver- Undersampled Magnetic velopment of an Adaptive wendung der ZF-Signale und Resonance Fingerprinting Zero-IF Receiver for Nar- Sensordatenfusion mit einer Data", Rheinisch-Westfälische row-Band Radar Applications IMU", Hochschule Trier Technische Hochschule at X-Band", Fachhochschule Aachen Aachen Zentarra, Michael: "Unter- suchung der Auswirkungen Schuth, Kim-Simon: "En- Thindlu Rudrappa, der Strahlschwenkung von twurf und Implementierung Manjunath: "Vitalparam- 5G", Rheinisch-Westfälische einer Automatisierungssoft- eterdetektion bewegter Technische Hochschule ware für das MIRANDA 300 Personen mit MIMO-Radar", Aachen Radarsystem", Hochschule Rheinisch-Westfälische Tech- Koblenz nische Hochschule Aachen

Slavov, Angel: "Imple- Ugurmann, Glen: "Entwurf mentation of an FM-based eines Spannungsreglers für multistatic passive radar using einen RFID-Transponder in a software defined radio", einer 65nm CMOS Tech- Rheinisch-Westfälische Tech- nologie", Ruhr-Universität nische Hochschule Aachen Bochum

Smarza, Sonja: "Design Valdes Crespi, Ferran: und Realisierung eines "Implementation of a dis- Frequenzteilers in einer tributed time and frequency SiGe-BBiCMOS Technologie", synchronisation system based Ruhr-Universität Bochum on two way time transfer", Spenrath, Tobias: "Develop- Rheinisch-Westfälische Tech- ment of an Adaptive Zero-IF nische Hochschule Aachen Receiver for Narrow-Band Ra-

67 ANNEX

PUBLICATIONS

To ensure that you have an up-to-date overview of our numerous publications in scientific journals and conferences, all of our publications are available with immediate effect on our website.

All publications 2020: www.fhr.fraunhofer.de/publikationen2020

Publications in scientific journals: Publications in scientific conferences: www.fhr.fraunhofer.de/publikationen2020-journals www.fhr.fraunhofer.de/publikationen2020-konferenzen

All Fraunhofer publications: http://publica.fraunhofer.de

68 69 ANNEX

COMMITTEE ACTIVITIES

Behrendt, D. Düsseldorf: Mitorganisator, Mitglied des Steering Committee Deutsche Gesellschaft für Zerstörungsfreie Prüfung (DGZfP): Zentrum für Sensorsysteme (ZESS) 2020, Siegen: Wissenschaftlicher Mitglied Beirat Deutsche Forschungsgesellschaft (DFG): Fachkollegiat Bertuch, T. IMA (Institut für Mikrowellen- und Antennentechnik e. V.): IEEE Antennas and Propagation Standards WG P145: Mitglied Vorsitzender IEEE (Institute of Electrical Electronics Engineers): Senior Member Brüggenwirth, S. IEEE AESS Germany Chapter: Secretary Klare, J. EDA Radar Captech: German Governmental Expert International Radar Symposium IRS 2020, Technical Program European Microwave Week (EuMW) 2020: Technical Review Committee Committee European Microwave Week (EuMW) 2020, Technical Review IEEE Radar Conference 2020: TPC member Committee 7th International Conference on Electrical Engineering, Computer Cerutti-Maori, D. Science and Informatics (EECSI) 2020, Technical Program Committee Inter-Agency Space Debris Coordination Committee (IADC): Natio- 13th European Conference on Synthetic Aperture Radar EUSAR nale Vertreterin in der Working Group 1 (Measurements) 2020, Technical Program Committee IEEE (Institute of Electrical Electronics Engineers): Senior Member ICP 2020 IEEE 8th International Conference on Photonics, Technical Program Committee Cristallini, D. NATO STO Group SET-242 "PCL on Mobile Platforms": Co-Chair Knott, P. European Defence Agency: CapTech Member Informationstechnische Gesellschaft (ITG) im VDE, Fachausschuss HF European Microwave Week (EuMW) 2020, online: Technical 4 "Ortung": Vorsitzender Program Member Deutsche Gesellschaft für Ortung und Navigation (DGON): International Radar Symposium (IRS) 2020, online: Technical Mitglied im Wissenschaftlichen Beirat, Vorsitzender Fachausschuss Program Member Radartechnik AGERS 2020, online: Technical Program Member European Association on Antennas and Propagation (EurAAP): Gewählter Regional Delegate Danklmayer, A. NATO Research and Technology Organisation (RTO): "Member at U.R.S.I. International Union of Radio Science, Commission-F Wave Large" des Sensors and Electronics Technology Panels Propagation and Remote Sensing: Member Chair of the 20th International Radar Symposium (IRS), Warsaw VDE-ITG Fachausschuss 7.5 Wellenausbreitung: Mitglied European Liaison for IEEE Radar Conference (RadarCon), Florence Deutsche Gesellschaft für Ortung und Navigation (DGON): Mitglied im Fachausschuss Radartechnik Matthes, D. Radar Symposium (IRS) 2020 Warsaw, Technical Program Commit- NATO STO Group SCI-332 "RF-based Electronic Attack to Modern tee Radar": Chairman International Radar Symposium (IRS) 2020: Technical Program Heberling, D. Committee European Conference on Antennas and Propagation (EuCAP) 2021,

70 Nüßler, D. IEEE Radar Conference 2020: Technical Program Committee VDI/VDE-GMA FA 8.17 Terahertz-Systeme: Mitglied IEEE (Institute of Electrical Electronics Engineers): Senior Member European Machine Vision Association (EMVA): Mitglied VDE (ITG) Member International Radar Symposium (IRS) 2020, Ulm: Technical Program Committee Wasserzier, C. NATO STO Group SET-287 "Characterization of Noise Radar": Chair O’Hagan, D. IRS 2020 TP committee member NATO STO Group SET-268 "Bi-/Multi-static radar performance IEEE Sensor Signal Processing for Defense (SSPD) TP committee evaluation under synchronized member conditions": Chairman IEEE AES Magazine: Deputy Editor-in-Chief Weinmann, F. IEEE AES Magazine: Associate Editor for Radar ITG-Fachausschuss 7.1 "Antennen": Mitglied IEEE Radar Conference 2020: Special Sessions Co-Chair European Conference on Antennas and Propagation (EuCAP) 2020: European Defence Agency: CapTech Member Technical Review Committee International Radar Symposium (IRS) 2020: Technical Program IEEE Antennas and Propagation Standards WG P2816: Mitglied Member EurAAP Working Group "Active Array Antennas" (WGA3): Mitglied

Pohl, N. Weiß, M. International Microwave Symposium (IMS 2020), Los Angeles EUSAR 2020/21, Leipzig/online: Technical Chair, EUSAR Executive (online): Technical Program and Review Committee IGARSS 2020, Waikoloa: Technical Program Member European Microwave Week (EuMW) 2020, Utrecht (online): European Radar Conference (EuRAD) 2020, Utrecht: Technical Technical Review Committee Program Member IEEE BiCMOS and Compound Semiconductor Integrated Circuits International Radar Symposium (IRS) 2020, Warsaw: Technical and Technology Symposium (BCICTS 2020), Monterey (online): Program Member Technical Program Committee, Co-Chair for MM-Wave & THz ICs Signal Processing Workshop (SPW) 2020, Vilnius: Technical Program VDI ITG Fachausschuss 7.3 Mikrowellentechnik: Mitglied Member IEEE MTT Technical Committee MTT-24 Microwave/mm-wave Radar, Sensing, and Array Systems: vice-chair Worms, J. IMA (Institut für Mikrowellen- und Antennentechnik e. V.): Mitglied IEEE Radar Conference: Technical Program Member IEEE (Institute of Electrical Electronics Engineers): Senior Member

Uschkerat, U. EDA CapTech Radar: German Governmental Expert BMVI Nationalen Vorbereitungsgruppe zur WRC-23 (NVG23): Mitglied ETSI TGUWB: Mitglied

Walterscheid, I. IGARSS 2020: Scientific Committee

71 72 LOCATIONS

The Fraunhofer Institute for High Frequency Physics and Radar Techniques FHR has five locations in North-Rhine Westphalia.

Head office and postal address

Fraunhofer FHR Fraunhoferstr. 20 53343 Wachtberg Germany

Phone: +49 228 9435-0 Fax: +49 228 9435-627 [email protected] www.fhr.fraunhofer.de/en

Institute branch Wachtberg-Villip

Am Campus 2 53343 Wachtberg-Villip Germany

Phone: +49 228 60882-1007

Research groups at universities

Research Group Research Group Research Group Aachen Bochum Siegen

Melatener Str. 25 Universitätsstraße 150 Paul-Bonatz-Str. 9-11 52074 Aachen 44801 Bochum 57076 Siegen Germany Germany Germany

Phone: +49 241 80-27932 Phone: +49 234 32-26495 Phone: +49 271 740-3400 Fax: +49 241 80-22641 Fax: +49 234 32-06495 Fax: +49 271 740-4018

73 IMPRESSUM

Publisher Editor in Chief Fraunhofer Institute for High Frequency Dipl.-Volksw. Jens Fiege Physics and Radar Techniques FHR Fraunhoferstr. 20 Editors 53343 Wachtberg / Germany Dr. Janine van Ackeren M. A. Jennifer Hees Phone: +49 228 9435-0 Fax: +49 228 9435-627 Layout and typesetting [email protected] B. A. Jacqueline Reinders www.fhr.fraunhofer.de

Wachtberg, Germany, May 2021

Images

Title: Fraunhofer FHR / Jens Fiege P. 34: Fraunhofer FHR / Andreas Schoeps P. 2: Fraunhofer FHR / Uwe Bellhäuser P. 36: Fraunhofer FHR / Andreas Schoeps P. 6 Image 1: Fraunhofer FHR, Image 2: Fraunhofer FHR / Bellhäuser, P. 37: Fraunhofer FHR / Rudolf Hoffmann Image 3: Fraunhofer FHR / Fiege, Image 4: Fraunhofer FHR / Wojaczek, S. 38: Fraunhofer FHR / Jens Fiege Image 8: Fraunhofer FHR / Knott, Image 9: Fraunhofer FHR / Herzer, P. 39: Fraunhofer FHR / Andreas Fröhlich Image 10: Fraunhofer FHR / Fiege P. 41 Image 1: Fraunhofer FHR / Uwe Bellhäuser, Image 2: NASA, Image P. 7 Image 5: Fraunhofer FHR / Welsch, Image 6: Fraunhofer FHR / Fie- 3: Shutterstock ge, Bid 7: Fraunhofer FHR / Fiege, Image 11: Fraunhofer FHR / Fiege, P. 42: Fraunhofer FHR / Uwe Bellhäuser Image 12: Fraunhofer FHR / Manjunah Thindlu Rudrappa, Image 14: P. 44: Fraunhofer FHR / Carola Welsch Fraunhofer FHR / Fiege, Image 15: Fraunhofer FHR / Jens Fiege P. 45: Fraunhofer FHR / Diego Cristallini P. 8: Fraunhofer FHR / Jens Fiege P. 46: iStockphoto P. 9: Fraunhofer FHR / Jens Fiege P. 49 Image 1: Fraunhofer FHR / Reinhold Herschel, Image 2: Fraunhofer P. 10 Image 1 / Image 4: Fraunhofer FHR / Carola Welsch, Image 2 / FHR / Alexander Shoykhetbrod, Image 3: Fraunhofer FHR / Shutterstock Image 3 / Image 5: DLR / Evi Blink P. 50: Fraunhofer FHR P. 11 Image 1: Fraunhofer FHR / Jens Fiege, Image 2: DLR / Evi Blink P. 51: Fraunhofer FHR / Stefan Wald P. 13: Fraunhofer FHR / Marco Gallasch P. 52: Fraunhofer FHR / Fernando Rial Villar P. 17: Fraunhofer FHR / Jens Fiege P. 53: Fraunhofer FHR / Thomas Bertuch P. 22: Fraunhofer FHR / Jens Fiege P. 54: Fraunhofer FHR / Uwe Bellhäuser P. 25: Image 1 Fraunhofer FHR / Shoykhetbrod, Image 2 Fraunhofer P. 57 Image 1: Fraunhofer FHR / Sabine Gütgemann, Image 2 / Image 3: FHR / Uwe Bellhäuser IMS Messsysteme GmbH P. 26: Fraunhofer FHR P. 61: Fraunhofer MEVIS P. 29: Image 1 / Image 3 Fraunhofer FHR, Image 2 Fraunhofer FHR / P. 62: Shutterstock Mies P. 63: Fraunhofer FHR / Stefano Turso P. 31: Fraunhofer FHR P. 67: Fraunhofer MEVIS P. 32: Fraunhofer FHR / Simon Wagner P. 69: Shutterstock P. 33: Fraunhofer FHR / Matthias Weiß P. 72 Fraunhofer FHR / Jens Fiege 74 Many lectures from our "Radar What is "Radar in Action"? in Action" online lecture series can now also be found on our By presenting our research results, we want to show what can be achieved with radar and how YouTube channel: you can avail of the possibilities. This is hardly possible in person at the moment unfortunately, so we launched the "Radar in Action" public online lecture series in 2020. The lectures are aimed at https://www.youtube.com/ customers, partners and interested parties from industry, politics, science and society. c/fraunhoferfhr

20 events were held in 2020 with an average of about 100 participants each, totaling over 900 people, many of whom attended multiple times. Over 93% rated the lectures as very good or good.

THE EVENTS ALWAYS TAKE PLACE ON TUESDAYS FROM 2:00 TO 2:30 PM. THEY INCLUDE LIVE PRESENTATIONS ON A RADAR APPLICATION – SOMETIMES INCLUDING LIVE DEMONSTRATION WITH THE HELP OF EXPERIMENTAL SYSTEMS AS WELL AS OPPORTUNITIES FOR QUESTIONS AND EXCHANGE. PARTICIPATION IS FREE OF CHARGE, ONLY REGISTRATION IS REQUIRED.

11.05.2021 TIRA als Sensor im Bereich Space Situational Awareness (SSA) SCHEDULE FIRST HALF YEAR Referentin: M. Sc. Nora Egli

18.05.2021 23.2.2021 DVB-S based passive radar imaging High-resolution imaging with a 240-Ghz radar with SiGe chip Referentin: Dr. Iole Pisciottano Referenten: Prof. Dr.-Ing. Nils Pohl, Dr.-Ing. Reinhold Herschel 1.6.2021 2.3.2021 Additive Herstellungsverfahren für Millimeterwellen- Parasol: Passive radar controls nighttime marking of wind Komponenten turbines Referent: M. Eng. Alex Shoykhetbrod Referenten: Dipl.-Ing. Jochen Schell, Marvin Friedrichsen (Parasol GmbH & Co. KG) 8.6.2021 The HORIS Project – How radar helps to protect pedestrians 9.3.2021 Referent: Dr.-Ing. Reinhold Herschel Radar schützt Fußgänger – das HORIS-Projekt Referent: Dr.-Ing. Reinhold Herschel 15.6.2021 Bildgebende Materialanalyse – SAMMI 3.0 16.3.2021 Referent: M. Sc. Sven Leuchs Ballast Condition Assessment in modern railways using RADAR Referenten: M. Sc. Thoetphan Kingsuwannaphong (RWTH Aachen), M. Sc. Stefan Rümmler

23.3.2021 Real-time SAR - live aerial imaging in all weather conditions Referent: Dr. rer. nat. Stephan Stanko

20.4.2021 Danger from drones: Monitoring airports with millimeter wave More info on our online lecture radar series and free registration at: Referent: M. Sc. Winfried Johannes

27.04.2021 Synthese von Radarrohdaten in Verkehrsszenarien durch www.fhr.fraunhofer.de/ Raytracing Referenten: M. Eng. Stefan Wald, Dr.-Ing. Thomas Dallmann RadarinAktion

04.05.2021 Machine Learning for Radar applications - Classification of Targets using Neural Networks Referent: Dr.-Ing. Simon Wagner 75 76